This is for legal reasons mostly. They don’t think anyone reads this so they went for the most blunt and transparent language, which also gives them the most legal certainty. The banner is missing the reject all button though, which in Europe is seen as required by many of the privacy regulators.
We tried cheap ones, but our kids get irritated skin from them. Pampers works for us. That being said, I’d go for the cheapest brand that works for the little ones.