Mathematics in general is a bunch of stuff that often looks useless to laypeople or even professionals and may look so for 200 years until it very suddenly becomes relevant and crucial.
The computer that you used to post your comment uses a lot of mathematical stuff developed in previous centuries. It is unlikely that Gauss or Euler could have predicted that their work (ink on paper) will one day be used to facilitate completely different modes of communication.
And it is well possible that some priest criticized them for wasting their talents on abstract things that don't help humanity as of 1800.