In terms of actual gameplay it’s quite irrelevant, so for me it’s just a matter of aesthetics and roleplay.
In a historical game as Italy I would never do it, as it would look horrendous, unless I were planning to go against Germany at some point.
As Germany, it depends. I sometimes want to annex them, but most of the time I like the nice borders you get with an independent Switzerland.
I wish you could make a proper partition of Switzerland with Vichy France and Italy based on the linguistic borders. That would be fun.