Floor bed vs crib?

Hi! My LO is alentó 5 month old and we are now thinking to move her into her own room soon and are contemplating between a floor bed vs a crib. A few pointers : 1. We are aware of convertible cribs but don’t wanna have to buy another mattress in a couple of years again. 2. We love the idea of baby not being constrained in her crib when she is a little older and can explore her room. 3. I think it might be easier for the baby too as she wouldn’t have to go through changes in bed as a toddler. I guess I am just looking for people who have used floor beds for small babies and tell me any cons if there are any.