Not every album that one may want to hear is available in every format. Not every version of an album that one may want to hear that is available in a particular format sounds good.
Therefore, it makes total sense not to be restricted to just one format, even if one believes that it is superior overall. In any case, that is questionable because personal tastes vary considerably. No one is entitled to dictate how others choose to listen to music.
In truth, all formats have their strengths and weaknesses. I find it pays to cover as many of the bases as possible.

