Not good for their development
As mentioned above, the bumbo seats unfortunately aren’t good for their hips and can actually hinder them sitting up on their own because it pins them into position and they don’t use their own muscles. Blow up seats are better. They unfortunately don’t come with a tray though.
We had a mamas and papas one (second hand) and used it from when my daughter was around 5/6 months to around 1 (she was on the small side). She could already support herself well when we started using it. We would use it for short periods of time while getting food ready in the kitchen. She really enjoyed it as she was clingy and this was a way for her to still be close to me. Most seats that holds them in place isn’t good if used for extended periods if they aren’t already sitting on their own.
I got my son the fisher price sit me up chair and honestly it’s a game changer! I put him in it and I place it everywhere.. the floor, the living room table and the kitchen counter and he just loves it. It allows me to do things while he watches. I read it’s better for the hips than the bumbo
Look at mamas & papas bug chair. It is hip safe.
We went for the Upseat because we heard the bumbo wasn't recommended for hip development. It's pricy but been great investment as doubles as a highchair
I’ve heard that bumbos are really bad, ergonomically. They’re not good for babies’ hips. Apparently we shouldn’t be forcing our babies to sit until they’re able to sit on their own.