A Bosu ball is a great piece of equipment for certain exercises.
I had to use it regularly when I was going to physiotherapy after my lower back injury.
It is also great when you want to advance exercises. It works well for ab exercises.
If you flip it over and grip on the edges of the bosu ball you can really challenge your
push ups. Or even challenge your balance on top of the upside down ball and do some
squats. It's a versatile piece of equipment but it isn't cheap. There are certainly other
pieces of equipment that I would suggest prioritizing (like dumbbells and bands) before
this for a home gym,