Floor bed/toddler bed

We have this exact bed for our almost 4yo. He went in it at 22 months. I also have a August baby, and I would not put him in it. He is walking, climing ect. We often go into big brother room for a book before bed and I cannot begin to tell you the stress from how much he climbs and how many times he has fell. He's learnt now how to get in and out properly but man it was stress!!!

I have something similar but is bang on the floor and double bed so much bigger and fully enclosed. She been in it since 6months old, no issues and sleeps all night, currently we keep it closed so she doesnt come out of it but can eventually take the gate out and have an opening like this one you show.

Mine has had a floor bed since 6 months, no sides on it, and an extra 2" mattress on the floor next to it as she rolls all over. It's been brilliant for us, means we can cuddle her to sleep/lie with her/ I used to boob her lying down together and then just roll away when she's asleep. She doesn't really get up to play in the night but sometimes gets the zoomies and does a few laps of her room (very funny to watch on the camera). Her room is totally babyproof of course, I'm living for the day when she puts herself down for a nap haha, not likely though, she gets too much fomo.