According to this large randomised trial [1], simple interventions to increase the use of surgical masks reduced infection by 11%, and by nearly 35% in over 60s.

That doesn't seem useless.

Of course, if you're only talking about protecting yourself from others, then a KN95 mask is clearly the way forward.

[1] https://med.stanford.edu/news/all-news/2021/09/surgical-mask...