Does anyone use it?
No. The people in the YouTube ads smile way too much for me to trust them.
I use my education to proofread my computer writings.
Work sprang for a Grammarly account for me, but when my computer was replaced last year, the software/subscription did not automatically carry over and I haven't bothered trying to reinstall it, since it now requires an IT administrator to do so. (I was able to install it, and lots of other software, by myself without needing an admin loginI get these weekly nag emails "we haven't noticed any activity from you in the past week" but it's too much hassle to try to get it installed.