Should Potions Be Purchasable If Inventory Is Full?

I do like how Riot made it so that the elixirs are automatically consumed when a player's inventory is full on purchase, so I wonder why potions aren't treated similarly.

The main idea behind this is that it would allow people to defend their bases a little better. Tanks would be able to buy a handful of health potions and have those slowly regenerate their health as they defend, mages being able to buy mana potions so frantic rapid-casting wouldn't be limited via mana (not like many champs would have to worry about mana by this point anyway though) and then health potions to help if they don't get taken down too quickly.

Right now, Homeguard seems to be the only purchase in the shop that is excellently tailored to defend your base when the enemy team is pushing. Couple that with gold being useless after 6 items + trinket + elixir, this provides an additional use for gold that will always be available and is far more beneficial to teams that are behind/defending than ones that are ahead/pushing, these would also provide more benefit for tanks that aren't as susceptible to being burst, and even more so ones like Mundo or anyone with Spirit Visage that values regen.

The only thing that would need to be adjusted to keep this from getting out of hand (unless there's something else I missed) would be changing it so that not only can champs not carry more than 5 of one potion as they do now, but they also can't stack more than 5 potions worth of regen effects.

If they did this, I can't see any champ in particular getting out of hand or having this negatively effect anything from champ select to strategy viability, so is there anything I'm missing in that department?