It may be good for hacker community, but for a third party manufacturer to embrace this approach, they would need to be reasonably sure that garmin won't simply patch this in future and nullify their investment
A developer has demonstrated that Garmin Fenix smartwatches can be made to accept running efficiency metrics from external ESP32 or nRF52832-based devices, bypassing parts of Garmin's tightly controlled sensor ecosystem. This may open up the way for makers to build unofficial Garmin-compatible accessories.