First, let me just say, writers and editors would be foolish not to make use of any technology that could be beneficial to the writing progress. Programs such as Grammarly serve a valuable function, and I always run clients' work through software before and after an edit, in case it spots something I missed. However, it's important to remember that when something is 'flagged,' it is not telling you something is 'wrong' per se. It is pointing out places where you might find something you want changed. It does not know if you meant to say its or it's, there or their or even meet, mete and meat.
A client once wrote to complain that after my editing, his book was rife with errors. He found errors. His friends found errors. His mother's maid's stepmother thinks she found some errors. I naturally pulled up his files, expecting to see a disaster but it all looked great. Then I ran it through an editing program, and in the first two pages alone, the computer raised 15 'red flags.' I proceeded to go through every flag, and lo and behold.... not a single one of them was an actual 'error.' Had I followed the computer's suggestions, it would have been a calamity. I surmised that is what happened with my client. I sent a sample page of why the computer's concerns were unfounded. I never heard from that client again.
The point is, technology is great when it works, and when you know how to use it, but it is a tool only; sometimes a great tool, but still, just a tool. Use it to assist you, but don't let it take control.