I think that all depends!!!
Personally, I'd use it for going with a theme you really want to go with. I personally like to theme towns after my interests, like witchcraft or space. So you could do the same if you wish!! Or to just do some pretty landscaping or get villagers you want but couldn't fit in your other town.
I'd name your character and town after the theme you pick for the town!!
And I'd make it your main town if it becomes your favourite, but if you prefer the other one more, make that your main!!!
I hope these tips were helpful.