I've also seen this in the US. The first time I officiated in the mid 2000s, I always had to wear jacket and tie to and from major conference college matches. Now with Covid limiting dressing room space, we are allowed to either wear business casual or tracksuits to games. I think as long as you have a nice tracksuit or a polo/golf shirt with the appropriate logo, that's more than acceptable. The world is changing. Even major college and professional basketball coaches in the United States, who have a number of people well-known for their stylish suits, have moved to much more of a business casual look (like how you see basketball coaches dress at the Olympics, for example).
On a somewhat related note, I think it's funny when the VAR team wears the exact same uniforms that the on-field referees wear even though they are sitting in a video room (and in many cases in a central location hundreds of miles from the game site). I think VARs are fine wearing a golf shirt and either tracksuit pants or business casual khakis, but that's just me.