There are several reasons for the strapping. Most times the bottom of the joists are not even, and you can shim the strapping to get your ceiling flat. Another is it will give you a wider area for the joints between the sheets (you're not splitting a 2x in half).
If the bottom of your joists are even and 16" OC, I'd screw and glue the sheets directly. Make sure you use the correct thickness and type for your application.
If the bottom of your joists are even and 16" OC, I'd screw and glue the sheets directly. Make sure you use the correct thickness and type for your application.
