The reason is that.. it's not, actually! Like, individual websites might do their own weird takes and have their own design systems which are mistaken for 'mat

The reason is that.. it's not, actually! Like, individual websites might do their own weird takes and have their own design systems which are mistaken for 'material design', but I don't think you can fault Google for making text boxes too similar to buttons. Text fields https://m3.material.io/components/text-fields/overview https://m3.material.io/components/text-fields/overview - underlined or outlined, have their title text Buttons https://m3.material.io/components/all-buttons https://m3.material.io/components/all-buttons - fully colored or outlined, may have a shadow, more rounded, differently-styled