I divided my 10 gallon, I think it looks cool to have two different styles in one tank.
You could even get plants that match the colours of each Betta. I have one plant in each of my 6 tanks that is the colour pattern of my Bettas. Really makes them pop. :)
Bettas - Giovanni (HM), Burly (HMPK Giant), Potato (EEHM), Vesper (HMPK).