Is the enough digital activity to make satellites useful to those who don’t do voice work? I’m mostly interested in grid hunting and operating from rare grids. I really don’t enjoy FM or SSB.
In general, probably not. If you want to get those rare grids in your log, you'll need to break out the microphone and try FM and SSB. You can put rare grids on the satellites using digital modes, but you won't get many contacts. Again, break out the mic, and you will get more contacts if you are on from rare grids.
Most digital activity is 1200bps packet (APRS) through orbiting digipeaters like those on the ISS and NO-84. Both are currently unavailable, but the ISS digipeater should be coming back on around the middle of this month. There is 9600bps packet available through FalconSat-3, and its digipeater is operational. I have links to some articles on how to use these digipeaters on my QRZ page.
Some have been using FT4 through the linear transponders. But you usually won't hear the numbers of stations using these modes, compared to the numbers to stations that you hear in FM or SSB. On the linear transponders, you'll probably hear more CW activity than other digital modes.
73!