Standing in a puddle of healing potion should not heal you as well.
Why though? Standing in a puddle of magical fire damages you, standing in a puddle of healing liquid heals you. I can see that happening.
The intended use of a potion is to drink it. So doing something else then drinking it should not give you the effect of the potion.
True, potions are usually intended so that characters drink them. But that doesn't mean this should be the only possible way of using them! Many people have a lot of fun with coming up with unintended ways of using items, spells, environment and so on.
I dunno ... it seems that im either blind, stupid, or ignorant ... or all abowe :-/ but i simply cant see even a single benefit in throwing a potion.
I can drink potions straight from my teammates inventory. > So why bother throwing it and waste action for that?
Then don't throw them - easy!
Also, buffing several characters with one potion by throwing it on the ground is a very smart move. Players tend to love feeling smart.
Feeling smart because you use an obvious feature of the game again and again ? Really ?
Well, I wouldn't say that it is obvious for all people. Some people find it obvious, some, when they come up with it, feel like they're smart.