My DD had one of those “next to me” cribs for her house which she used for the first 6 months then moved up to the full size cot.
I have had my 4 DGC for overnights since they were just weeks old (they are 13,11,9 and 1) and the older children obviously have their own beds, but the baby has a full side travel cot that I can put away as I don’t have a lot of room and only 2 bedrooms.
Mind you the mattress that comes with a travel cot is never very good so I bought a proper mattress to sit on top. It’s ideal and the baby sleeps very well in it.