I have two characters in my town; my mayor and Fishie. I made her so I could display the other furniture sets I like without just tossing them in storage or my museum. I use Fishie to create clothing and I use my mayor for paths and pattern art. You also get double the unorderables, DLC's and holiday specials, so there's a plus.
If you have a certain villager that you want gone, you can make a second character and have it talk to all the villagers you want to keep, but ignore the ones you don't want. One of the ignored ones may ping you to move out.
Finally, there's a weird thing that sometimes happens where if you go on one character and a villager pings you to move and you accidentally say yes, then you go on your alt and that villager pings you to move, and you choose yes again, the villager will change their mind and stay in town. I think this works vice-versa too, and if it does it's a great life-saver.
So if you have the room for another player house, I say go ahead. There aren't too many downsides to it.