I have quite a few tanks, including 2 doubles sets with boots. All drain just fine and show no signs of rust. I check under the boots maybe every 3-4 months. These tanks are 4-7 yrs old, used often, in low-saline seawater maybe monthly and generally receive no rinsing of the tank. The tanks are kept in areas that are dry and relatively warm and I've had no signs of surface damage whatsoever.
I occasionally get pressure to take the boots off apparently mostly because it's not cool. I'm not greatly moved by that arguement.
I think not having tank boots is a pain in the neck (only about 18" lower). The tanks don't stand (yes: secured, not just standing) or lean as reliably and bare bottoms risk denting and scratching many surfaces including wash room tiles, and my household's wood floors, and the wood surfaces on many boats. Boots serve a good purpose and if you aren't actually diving in caves or other confined spaces you don't need to take them off just because some folks think they aren't cool.
I'm not 13 anymore.