While similar to (current) background, it would add a jump in useability as the reference image could move and zoom with the camera. Whereas right now it’s quite awkward, as I find I’m constantly repositioning and fiddling with camera repeatedly to check different angles.
Ability to have multiple references at different angles can also be useful.
A two plane object tool that you can load a separate colour image on each side would be a big benefit.
You can fudge this at the moment by using the plane object and turning an image into an alpha and adjust the material settings. Not perfect but it can help.