N5 and N4 are pretty much useless as a certificate, and N3 is sometimes asked for by stuff like eikawas or packing factories, stuff like that.

I think the experience can be useful practice for some but really depends on the person.

I did N3 twice and both times were really good practice, and between them I realised how to learn between the tests to improve the most, like especially realising I was such a slow reader.

But the test day is a real pain. You sit there for 30 mins whilst they check everyone's ID, shout stuff at you, then you sit a 30 min test, wait another 30 mins for them to collect the booklets, more shouting, stand in a corridor for an hour while a load of teenagers shout at each other and play tig, then repeat 2 more times.