I think it's important to distinguish between the purpose of regular chocks and a product like X-Chocks. Regular chocks are needed to keep a trailer from rolling away, but they do little to stabilize the rocking motions of the trailer. X-Chocks stabilize rocking motions by limiting suspension movement, but they are not intended to keep a trailer from rolling away. With enough force to get the wheels turning, X-Chocks will just pop out anyway. Been there, done that.
So if you want to keep the trailer put, kick in regular chocks on each side. If you want to limit bounce inside, install an X-Chock between the tires on each side. I use both and consider it money well spent.
Regarding parking brakes, they may eliminate the need for regular chocks but would do nothing to stabilize a trailer.