No way would I use Shark Bites or the equivalent on a customer's house. I've used them on mine, but only as a temporary solution. Sometimes that temporary solution has lasted 2 or 3 years before I can get to it again. For a job that's for someone else, I wouldn't risk a callback.
We used Shark Bite connectors for Pex to Pex and Pex to copper in my master bath remodel, about 5 years ago now. Most definitely inside the walls!
So I am just a homeowner and DIY-er with these connectors, not a contractor. I wonder why, as a pro, you would not use a Shark Bite in a customers house, or as a long term (permanent) solution in your own house.