Just my 2 cents here.
I believe there are some of us who want the retrievability of using a screw-mented prosthesis/bridge.
If both the custom abutments are engaging while correcting the angulation of the cemented restoration,
it would not be possible to unscrew to remove the prosthesis by accessing the screw channel. Obviously,
if the screw channel is at the facial, it makes it harder to retrieve for routine maintenance, but if the
implants exit off the lingual or occl, but are just angled towards each other, a screw-retained restoration
is still possible after the prosthesis is luted on the cast and you can insert by screw only.
Again, not every situation is the same, just saying.
LCM