Should I use push-to-connect fittings for PRV installation?
SharkBite and other similar self-sealing insertion products are deemed reliable for long-term use (SharkBite are actually guaranteed for 25 years). They're tried and true at this point, having been used for quite a few years. Of course, performance depends on your technique. It's important to de-burr and de-flare the pipe end.

The fact that you're installing a PRV isn't really relevant. Whether it's appropriate depends on your usage scenario and personal preference. Do you have space to work with this type of fitting? Are you willing to spend the money on them?

SharkBite connectors can be removed with proprietary tools or DIY methods. Whether that's a good strategy is entirely your prerogative.