Are "encourage immigration" National Focus option useless?

[GAGA Extrem]

The NF works, but usually it cannot override the immigration logic itself (which is usually the most important factor). All it can do is increasing the stream of migrating pops if they would already perceive your country as a potential target.
And (iirc) it is mostly meant to attracted foreign pops, not direct your internal migration.

 

[GAGA Extrem]

I stand corrected. I had the PDM version of the NF in mind, not vanilla.
In vanilla it does only re-route a part of the migration streams by making it more likely that pops coming to your natino or moving within choose that province as their target. It doesn't increase immigrant attraction at all.