Polish is a language. polish is what you rub into shoes. On most of the web the two collapse into one, because software likes to flatten capital letters before it thinks.
Linguin treats them as what they are: different words. Each gets its own entry, its own definition, its own address. The capital is not decoration, it carries meaning, and the meaning is kept.
It goes further than one pair. English capitalizes nations and months, German capitalizes every noun, acronyms shout in full caps. WHO is not who.
And you don't have to capitalize correctly to search. Type it lowercase from your phone or all caps by accident, Linguin still takes you to the word you meant. Precision in the pages, forgiveness in the box.
A dictionary that ignores capitals ignores words. We stopped ignoring them.