Curing or not curing resin prints, it’s really up to you.
The prints have different material properties depending on if you cure them or not. Which property do you want?
For example, I printed a guitar pick using ApplyLabWork’s black, which is much like a Formlabs Engineering resin. I did not cure it, as it remains a little more flexible and less brittle when not cured. When you cure this resin, it is much more stiff but the risk of chipping is a little higher.
For most purposes I think standard resins are better-off cured, but it all depends on what you are going to use the part for.
As far as I know, the only resin’s where you never want to cure would be wax, and the only resin where you’d always want to cure is the ceramic and high-temp resins. Everything else, it depends on your application.