I suppose one potential drawback is that the visibility of the logic of a plugin is inherent in the pi ts extensions, and unless it's shipped with the rpi (pi-rust) extension, it may not be the same to use it. There are instances where I've seen pi go digging around in it's own docs & code to figure out how to do something.
There is a tool named Docs that guides users on how to use RPi and how to write extensions. RPi has a plugin ABI to support extensions.