One thing I do know is, the larger the seat the more comfortable it is. That is for me. Not everyone is the same. The seat I am using at present is one of the largest ordinary seats commonly available. It is actually not a lot smaller than the one in the picture.
I have not bought one of these. But if I find the delivery price is significantly cheaper in the future, I might buy one or two. If I do, I will see what I think of it.
It is also possible I might find a different very large seat.
We have to wait to see what happens in the future.