Possible benefits: while it increases review burden slightly (every PR to main still maybe requires 2 reviews), it will hopefully force people to do much smaller PRs (beause no-one likes massive PRs, and it scares people off from vollunteering reviewing) and generally will increase reviewing frequency across the community - so you'll have a much greater chance of rapidly finding a reviewer.

While trunk based development is a great approach, I honestly do not think it's a good fit for nf-core. Trunk bases development and continuous integration work well for coherent teams. The biggest benefits come from people pair or mob programming and doing away with reviews entirely. And I cannot see that really working out in general. As we are mostly working as globally distributed groups of volunteers. Perhaps it could work for tools or other infrastructure where there are a few dedicated people working on it.