If they see you going to spend what they would consider a large amount of money on a fancy restaurant, or other items, they might question such an action and it’s necessity rather than letting you move forward.
It’s not always an easy thing, I know and I feel your pain.
Although this may be seen as an advantage by some, it can make it difficult to truly gauge her interest levels in you when she puts her number in to your phone, though may never reply back to you there after again.
The general population of Poland has quite a good command of the English language, and Polish women will be able to hold at least an intermediate conversation with you in most cases.
However, dating is a little more complicated and not what many people think.
This is not the 1980s and Poland is not the Soviet Union, nor was it ever.