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There are two main reasons I use in-game aliases:
It gets around the 10 command limit that you have with the command separator. This isn't normally an issue, but there are certain situations where I'll have a lot of conditional requirements on attacks; wielding, getting vials/pipes from pack, etc. It's easier to not have to worry about whether or not I'd hit that limit.
It means I don't have to requeue to change the commands to run as part of my attack, which in turn means I don't have to remove other things I may have queued (movement, blocking, picking up gold or corpses, etc.) if I decide I want to use different venoms, switch to targetting a different limb, and so on. I can just queue the alias once, and change what commands are associated with it as many times as necessary before recovering balance.
Something where you created a bug and he revives you in exchange for you being mum about it.