Actually, I like such "triggered" stunts even more than the original stunts, because they feel less "mechanical" or "meta", however you wanna call it.
Normally, most stunts are built around "meta" thinking. Like, you get +2 when rolling [action] with [skill] in [trigger] situations – the only thing rooted in the narrative is the last part. Or, use [skill] in place of another skill during a challenge, allowing you to use [skill] twice in the same challenge. Or, use [skill] for rolls that you’d normally need [other skill] for in [trigger situation]. That's all a bit detatched from the actual narrative happening in-game.
"Triggered Effects" from the toolkit are somewhat different, as the central part of the stunt are not some "meta conditions", but narrative triggers. It's like, whenever you are in [trigger situation], roll the dice to gain [specific narrative permission/denial]. There's some mechanic involved, of course – the skill roll – but the stunts are built around the narrative, and the effects are of mainly narrative nature, too.
I like that, because it helps to reinforce who the character is in the fiction, rather than making him "more mechanically awesome". (And it helps counteracting the usual "Fate is way too meta!!!11" rant as well.)
And yeah, that's quite similar to some – not all – of the moves from Dungeon World.
Like, "when you consult the spirits that reside within your signature weapon, they will give you an insight relating to the current situation, and might ask you some questions in return, roll+CHA." (Fighter's Heirloom move), or "when you hold your holy symbol aloft and call on your deity for protection, roll+Wis; on a 7+, so long as you continue to pray and brandish your holy symbol, no undead may come within reach of you, on a 10+, you also momentarily daze intelligent undead and cause mindless undead to flee." (Cleric's Turn Undead move). Incidentally, the last one is almost identical to the Not to Be Trifled With "triggered effect" stunt presented in the toolkit.
But while you can get some inspiration from DW (or other *World engine games), don't forget that it has many other moves that are quite similar to "ordinary" Fate Core stunts, too, in that they're mainly mechanical in nature.
Like, "when you spout lore about a monster you use WIS instead of INT." (Ranger's Familiar Pray move) or "when you’re outnumbered, you have +1 armor" (Thief's Underdog move).
I consider DW's "narrative permission" giving moves the more interesting ones, but that doesn't mean the others don't have their place. Same way, I consider "triggered effect" stunts actually more interesting than the "ordinary" ones, but that doesn't mean they're superfluous or bad.
I think the important part for Fate to remember is that "triggered effects" don't just add story details or give you narrative permission to do something. That's what aspects for. Like, if you've got A Friend in Every Port as an aspect, that's what you have.
You can go drink beer with him or have a nice chat – but that doesn't mean he's per se useful for game purposes. That's what normally "declare a story detail" would be for – I've got this friend here, and y'know, he also happens to have heard something. Or I've got a friend, and he's actually willing and able to help us in some way despite possibly bringing himself into trouble.
A "triggered effect" stunt bypasses that necessity. It's function is basically quite similar to declaring story details, but you don't have to spend Fate points on every single occasion.
It has to be more effective than "regular" Create an Advantage or Overcome rolls that don't require a stunt, too. Sure, you might try to convince an acquaintance to help you despite some risks, if you find proper "leverage" (to use the DW term). But the A Friend in Every Port "triggered effect" stunt gives you a "shortcut": If you succeed, he ows you a favor (tell me what it is!). Even if you wouldn't have "leverage" otherwise, he'll help you, because favor is favor.
I'd be totally okay to ditch that skill roll necessity for some minor "triggered effects" as well. That's taking a leaf from DW, too, which has a number of such moves. There are moves that require a roll to achieve their effect, and there are others that give you a narrative edge simply by having them, but aren't as potent as those that do.
Like, "after you’ve used a poison once it’s no longer dangerous for you to use" (Thief's Poison Master move), or "When you have time and safety with a magic item you may ask the GM what it does, the GM will answer you truthfully" (Wizard's Enchanter move).
That's admittedly somewhat close to the narrative permissions aspects grant innately. But I think it has it's place, too, in some situations. I find it difficult to give any guidelines when I'd require such a stunt and when having an aspect alone is sufficient, because it's totally up to the genre you're playing. The closest thing to a guideline I can currently imagine is: If it allows you to kinda auto-succeed a roll you'd be otherwise required to pass, it's probably worth a stunt.
Man, that post got way longer than expected, and I'm used to writing ridiculously long comments...I hope I came to some kind of point nevertheless :)