Testing the Grammarly keyboard to see if it can help with my writing

Testing the Grammarly keyboard to see if it's any good.
Grammarly helps you write mistake-free in Gmail, Facebook, Twitter, LinkedIn, and any other app you use. Even in text messages!

I can't see any huge benefits of using it over my installed Grammarly app though.
What happens if I switch keyboard to Gboard and check the text afterward?
It seems to work great too. If this works with external keyboards then it could be great for me while typing in English. So if I have to type on phone I can use Gboard, and then switch to Grammarly to correct everything. And when typing on an external keyboard, I can use Grammarly to correct in real-time eventually. I'm not sure I can use a Swedish keyboard then though. I mean a Swedish external keyboard with Grammarly because it only supports English.

Their sophisticated grammar checker scans your text for common grammatical mistakes (like misused commas) and complex ones (like misplaced modifiers). Write with confidence, even on your phone.

Maybe it's still better to use my GrammarPal directly in any app instead of this keyboard?