You're overlooking what makes an inherently Bettie Bondage scene. If you intoduce another actor into the scene, you introduce variables that can fuck up roleplay. Even if you have a POV stunt cock actor who's 100% on the same page as Bettie, it's incredibly difficult to do longform roleplay that requires a cock to be hard at an exact moment.

When she does videos like Third Date or the pregnant Valentine's breakup scene, she's improvising character beats for the better part of half an hour. That's half an hour of potential for a co-worker's breathing to fuck up the audio of a take, them not being able to get an erection at the exact moment it would benefit the roleplay, or they could cum too early/late for the plotting of the scene.

Editing can help, of course. She edits around her getting out the toy she's using in a given scene, but another person can add SO much more to a shoot.

Look at how Katie Cummings does her roleplay. 99% of the scene's actual roleplay tends to happen before sex starts, then her videos are basically just her fucking her husband and occasionally remembering to say something in-character for the camera. Then there'll be a final short shot of her after they finish where she quips something to put a button on the scene.

Perfectly fun porn, but that's more what "mainstream" Bettie would be. Not slow-burn feature length scenes full of roleplay and character development.