Same reason as Deacon & Vivi,
Further is the asymmetrical feel as I like my knives ambidextrous. Same reason I haven’t got any comp lock. My OCD hates knowing one side is weaker, because the liner is cut.
A lot of frame locks have the pivot ‘hanging’ on the lock side because the lock cutout is wide, the the center of the pivot is on the side that isn’t connected to the butt of the handle like this: https://www.gpknives.com/boker-plus-vox ... bo336.html
The pivot is hanging off the frame that holds the whole knife, which makes it worse IMO.
I haven’t seen any Spyderco like this, and Sebenza also doesn’t have this design weakness.
Some like this is even better:
https://www.knifecenter.com/item/BM765/ ... um-handles
Having said that, I don’t like asymmetrical handle.
Strangely, Military with it’s ‘insert’ liner lock doesn’t bother me as the strength of both sides are by the G10. If only it doesn’t have that release cut out making it feel asymmetrical.
The only liner lock I keep is GB1 and the ball is flattened, about 1/4 of the ball radius.