Yet for some reason Soraka is still able to heal minions and Karma can still shield them.
I don't understand the huge advantage of being able to do so, so if anyone can give me a good reason as to why this is still allowed, I would be delighted.
Last hit prevention. I do it with Alistar all the time too, pop a heal right before they AA to deny the last hit. I'm not a fan of it on Soraka, because my health is more important than a minion's.
I use Soraka's heal and Karma's shield on minions when pushing if no one in the enemy team's around and I like it tbh
You can use it to prevent the enemy from last-hitting, it typically baits them to stay around long enough to get hit by Starcall as well, since they'll predictably stay to try to last hit the minion if it's still alive. It's also used for when minions are tanking the tower for you, so you can heal them to allow them to keep doing so for a bit longer (or for ages, depending on your AP and CDR).
It works well with Banner of Command too.
