0
Lots of people here have used GPS loggers at the track. The latest feature being added is lean angle measurement. Google/YouTube search "GMOS JI100T" for an example. Overall, I'm not convinced knowing your lean angle would make a meaningful difference to your riding.
My two cents...
Lean angle is the result of your riding inputs (confidence in tire grip, decisiveness of your inputs, speed, body position, ...). We've been doing fine exploring max lean at the apex, an electronic gizmo is not a game changer. But what about entering brake zones, like NHMS T1? You're at max speed, then pre-turn, while the bike is leaned over (a little) you start braking. I’m not sure, maybe measuring lean angle could be helpful, and help experiment with body position that minimizes lean angle during braking.
So let’s hear your thoughts on it...