Having your left hand on bottom could make it somewhat uncomfortable, or add a bit of strain. The bag will rest under your left arm. I play warm wind smallpipes, so I can’t comment as to how that would affect play with bellows added.
If you ever want to play low D, you might find that some of those have an offset bottom hole to make fingering easier. However, if you play with your left on the bottom, you won’t be able to reach it.
As stupid as this idea seems, after 4 years I have thought about reversing my hands to compensate for what seems like a weak right hand (I am naturally left-handed). In fact I have tried this with rather bizarre sounding results.
I told you it seems like a stupid idea.