Depends on the deserts in question and knock-on effects: Saharan Dust Feeds Amazon’s Plants.
* https://www.nasa.gov/centers-and-facilities/goddard/nasa-sat...
Helping vegetation in one place to grow may hinder it somewhere else. How important this is still appears to be an open question:
* https://www.nature.com/articles/s43247-020-00071-w
I'm not sure if humans are wise enough yet to try 'geo-hacking' (we're already messing things up: see carbon dumping).