Why would you ever waste your money on Sharkbite fittings in the first place? They are the most god awful expensive fitting when you could use a fitting that costs $0.50 a piece as opposed to several dollars? They are bulky, expensive, non-rigid.
The PEX air line thing is a rabbit hole of a conversation that Im sure youve already read about with a simple google search.
Ive been using PEX in construction for almost 30 years and have no problem with it for small air distribution (we run 175psi mains and none larger than 1"). It is not rated for air distribution which Im sure you already know. Its never going to fail like PVC in shards but you will proceed at your own risk.
I would never use sharkbite only for the waste of money, I would never use them in plumbing other than in a situation where I couldnt crimp a proper fitting for the same reason. Trusting you air (or water) to an o-ring behind a thin stainless steel grab washer doesnt leave me with a good nights sleep.
Brass fittings, crimped with either a full copper crimp ring, oetiker style clamp, or expaner, I personally have no issue with it even at 175psi as long as your not near heat.