why hotel management is a pretty useless thing to study?
Because far too many people study easy, math-free subjects like hotel management, recreation and tourism, so there are way too many graduates each year for the few management jobs available. Everybody wants to be a manager, so management courses are very popular, and therefore useless.
Also, you don't need a degree in hotel management to get a job as a hotel manager. You don't need a degree at all. It's not rocket science, and the employer will train you in all you need to know anyway. Why spend three or four years getting a degree in something you can learn in a couple of months. Your chances are probably better if you have something like an accounting degree and certificate.
The WORST way to get into management is to study management (unless it's at an incredibly good school, not someplace in Poland). Study something useful, like the fields that I mentioned above, and you will earn a lot more than any hotel manager makes.
Also, if you think that you are going to get a job as a manager in Germany or Sweden without advanced knowledge of those languages, forget about it. And studying in Poland is not going to help to much because Polish is very different from German or Swedish. Your much more likely to end up as a low-paid chambermaid.
If you want a better life for yourself, think big and think math. Lots and lots of math. And study highly paid fields like financial engineering, financial mathematics, econometrics or petroleum, geological or biomedical engineering. If your studies are easy and not math-intensive, chances are high that you will end up earning little money, if you find work at all.
Sorry, but studying in Poland rarely makes sense for foreigners, and you are no exception. And studying management rarely makes sense unless you go to a top school. Best work, work, work at the math so that you have a very high chance of following a successful, highly-paid and satisfying career. Even if it means taking a year or two now to bring your math up to the level that you can study something serious, it will be well worth it. Your children will love you for it.