Works in Germany, Poland, and every other European country I believe.
Itīs the same as not changing to Euro, not going to drive on the right hand Side of the road, not going to do anything they do across the Chanel.
There are different legal and administrative systems from UK in most Continental countries.
For example in many countries everybody has to have a registered address. Not so in UK, except one is recorded on one day every 10 years on a Census form, but you could be anywhere else in the next ten years.
In UK, except with certain exceptions, it is not permitted for different government departments to share personal information with another department without the individual's permisson.
As for adopting the Euro I think there are 7 EU countries, including Poland as you know, which have not done so.
There are many Treaties and agreements which many countries adopt, but which many countries choose not to adopt. A trawl of international treaties is littered with them. For example International agreement on compensation for passengers injured or killed in aircraft accidents was originally under the Montreal Agreement, later Guadalejara and then Montrel Protocol. Since then there have been addendum agreements, which have only been signed by some of the original contracting parties. They even use different defintions of the currency to be used. Countries also adopt (Sign) Treaties but never ratify them, so they are not bound by them.
So to single out UK as not aligning with EU countries is very selective.
I seem to remember you being happy to shop at Polish S/Markets and buy diesel at Polish prices, which may still be low because Poland did not join the Euro and kept control of its own currency. Also one can still get change of 0.25 of an English pence - not in other countries. So alignment is not necessarily good.
I rest my case- and I need a rest anyway.