It just comes down to action and sensitivity. You can go pretty low on line weight with the right reel, but they're expensive, and you can always tie on a lighter leader. And if you're fishing strictly vertically, casting distance obviously doesn't mean anything, but you won't get very far if you can't keep contact with your rig.
To me, though, you're going to want to do more with your finesse rod than dropshot roboworms, so having an all around more versatile setup is more important and that's easier and cheaper with spinning gear. The only downside is having to use spinning gear. Are baitcasters more or less effective for finesse techniques? Probably not. Is going the bfs route an indulgence? Probably. Ultimately it's up to preference.