I can't think of a recipe that you can only handcraft. Can you give some examples in the description?

I've gotten reasonably far with a BNW game and not encountered this problem.

If you apply BNW to a vanilla game then no, you won't need this mod. Its more for when you combine it with a mod pack that does require it.

For example Pyanodons HighTech mod (https://mods.factorio.com/mod/pyhightech) has such a state where you need to make basic electric boards to get a factory that can create those. Normally you get a expensive hand craft recipe to close this gap, but no such luck with BNW

Ahh, that makes sense. I've played just a little bit of Seablock and I think there were some things in Bob/Angels that fit that criteria as well. Thanks.