I get the frustration and why it should work better. But then, why still use guest checkout ? I totally stopped and will register an account wherever I give my

I get the frustration and why it should work better. But then, why still use guest checkout ? I totally stopped and will register an account wherever I give my credit card. The difference with guest checkout is usually infinitesimal and I actually want to keep somewhere (in my password vault in this case) the places that have my full info and where to contact them.