A bit more than juste read your own writes actually:
The paragraph below also covers at least a part of your question.
And this doc answers completely your question I think with the table of guarantees:
But to sum up, it’s a trade off. Test first with w=majority and readConcern=majority. If the performances are “good enough”, then you don’t have to make a trade off. You can then start to trade some of the consistency for speed, but my advice would be to do it step by step and maybe prefer an upgrade to SSD or a better CPU or network before doing a trade off. It’s very use case dependent as well. For some use cases, the trade off isn’t possible so the hardware path is the only solution.
Cheers,
Maxime.