I often get emailed about non-continuous trait data that fundiversity doesn't handle.
I wonder if we should write a full vignette to show the general workflow, an include this in the error message for non-continuous trait data.

The workflow would go as follow (with a worked through example):

1. Identify the nature of all of your traits (binary, fuzzy-coded, categorical)
2. Compute a dissimilarity matrix between your species of interest (Gower's dissimilarity or its extensions from Podani or Pavoine)
3. Project this dissimilarity matrix onto continuous axes through a Principal Coordinates Analysis
4. Select a number of PCoA axes and interpret them using correlation with original trait data
5. Use them in fundiversity

I don't think it would be necessary to add any feature to fundiversity to deal with this case, as it's covered extensively by other tools (especially mFD), but maybe having a long-form documentation could be helpful to point users to.