Any benefit to publishing blogs from other niches?

I’m regularly getting requests to post blogs to my website. If they were scuba related I accept them normally. But what about outside the niche?

Example: a scuba website and a first air provide wants to write a first aid blog for us. It could be written in such a fashion to be scuba relevant, of course.

But help me understand how I can benefit with SEO on this, if even possible?