For using bitblik as a maker you don't need to use the BLIK system, you can buy something online in some polish amazon-style website, choose to pay with BLIK and then request a code in bitblik. Of course if you physically in Poland visiting you can also in most shops/restaurants/ATM use bitblik in similar way. As a taker you need to be able to generate BLIK codes which usually means a polish account or polish residence proof which revolut supports.