I agree, wait and see..

On the Ikea day bed, that is what DS has - transitioned from a cot at about 2.5. I think it's practical as it'll change to a double when he's older, and the storage under is handy. A bugger to make as you're tucking sheets down under the sides iykwim, but that's the same with most beds and no different to a cot. I'm just used to ensembles with nothing on the sides!