Believe it or not perlite holds a whole lot of water... but your 100% right... if you aren't using it for Hempys or top feed something (not mesh pots) you'll end up with chunks everywhere....
but a more there isn't a medium that's more inert, has better water retention, breaths as well as you can get aside from flooding hydroton or grow stones, and can be used like coir in a sense u can use a tiny pot and grow a monster plant in it with no ill effects..... but as I said, flood and drain, dwc, aero.... perlite just was not made for that application.. I used perlite for years as a soil amendment and not until with the past 6 months did I realize it holds massive amounts of water as well as it breaths...
Right now I basically took this guys method of hempy buckets with perlite & 2liter soda bottles and converted it into a flood and drain system with square pots but bottom fed by a typical flood and drain pump, res and table...and had to switch up to hydroton and grow stones because obviously flooding perlite filled containers isn't gonna work... but I gotta say I got some kinks to work out and fine tune but it's working as I'd hoped... the only major change I might make once I see it's holding me back is pot size...I'm running 5"x5"x7"tall squares... if I don't get the yields I like I'll jump to 6x6x8's I believe the next jump but so far all issues are of my lack of knowledge in the hydro feeding department and dealing with new strains where finishing times are different...even with known strains finishing times are different... sooner in most of the cases so far....