Some people like scribbles on their comics, some don't.
I think the heart of the issue is, the two camps. By doing the scribble, you reduce the resale pool, if you decide to ever part with it, or you leave it to your kids and they decide to sell it.
But hey if it is your funny book, and you want scribbles, and it makes you happy- go for it. Maybe you will keep it forever and it makes you smile- win! You may even find somebody willing to pay you gobs of money for it down the road. Just not as many as you may have hoped.