Not useless.
I have a US B1/B2 visa, and an FAA CPL/IR. So I can, for certain purposes fly professionally in the USA, or I can fly an N-reg aeroplane professionally in the UK. There aren't actually many people with the combination of professional licences, and a PhD in flight mechanic - so that means I can be useful in certain narrow niches, and I like being useful. [I think that the UK has four people with both a CPL and an aerospace engineering PhD - we all pursue the paths that work for us.]
I've had visas and permits permitting me to work in a whole bunch of countries in my life, and as I do scientific and test flying, there may well be reasons that I am the best person to do that flying. So I've elected to grab an EASA CPL whilst I could easily - enabling possible future tasks, but being fully aware that I may need additional permits. That's my choice, it doesn't stop the UK being both my country of residence and, once things have settled out a bit, my main country for pilot licencing.
Things are perhaps rather different for an airline pilot or flying instructor, that's a rather more common skillset, so getting the work permits may be harder.
My fundamental point however is universal. Given that you need a suitable visa or work permit anyhow - why introduce additional barriers? There is no sense in it.