There are some valid reasons for having a real camera bag or case. For example, so that you can carry extra batteries, SD chips, maybe filters, etc.
But I'll bet 90% of the time, all you really want is protection of the camera itself from physical damage, etc. The camera already has a carrying strap. Why do you need another one on the case itself ?
This stretchy foam case will provide the desired protection perfectly well, and give quick ready access after you have stretched it a bit (initially it is a tight fit).
For air travellers, in these days of luggage restrictions, it works as packing protection and saves valuable weight compared to the usual "real" camera bag.