Technical levels do not provide movement, but it tracks significant levels of movement. How data approaches, meets, exceeds these technical levels gives us indication of a next possible move (no matter what the data is).
Retracement is reasonable in all movement, nothing can go up forever and nothing can go down forever. Trend works in all charts showing you the momentum direction and strength (or lack of). I believe fibonacci can certainly be used (or should be used) in much of the same thought (it is not about mass levels).
If trend is looking for momentum and direction in an overall move, then fibonacci measures that amount of movement and can be applied to the whole move, a portion, or just on leg. If you have an A/B, it is significant when a portion of that move is taken out with a counter-move. The counter-move is the retracement. Trend lines are actually a very similar type of technical indicator, just more visually appealing.