When I use my flash bracket, I bolt the flash bracket to the camera. When I use the camera with flash bracket with my tripod, I bolt an Arca Swiss compatible plate to the flash bracket using another 1/4-20 hole in the bracket. A third 1/4-20 hole allows me to leave the $0.75 1/4-20 eyebolt (stainless steel no less) I use for a carabiner + neck strap on the flash bracket.

That said, from an engineering perspective the long term durability of a plastic molded dovetail when clamped in a metal Arca Swiss clamp might be a challenge because the Arca Swiss system is not designed around that degree of dissimilarity of material hardness (not that I have anything against plastic). One of the characteristics of Arca Swiss connections is that they are not based on a formal standard and this leads to minor dimensional variability among components that is mitigated by clamping the clamp tighter or buying components from a company like Arca-Swiss at the prices their products command.

Potential durability aside, a molded in dovetail would increase the bulk of a camera and generally the trend seems to be away from camera bulk all things being equal. While a molded in adapter might increase stability in some cases, in others it would decrease it. Setting a camera on a table is an obvious case. Any other mounting is also going to be through a longer lever arm and with a higher center of gravity.