Just had a few matches recently and I keep seeing defenders selecting bottom lane and I may be unaware of something but I was under the impression that defenders should be going top because of the way their built to sustain and be fine early game, so support and a damage (attacker, all rounder, whatever) goes bottom lane for the extra audino exp. If there's a legit reason defenders can go bottom lane then okay, but I'm looking for help to understand this tactic.

Edit: ty all for the feedback. I haven't really seen defenders do this til recent and assumed defender top lane was the norm considering it auto suggests top lane and ranked up til now they all pretty much went top