Recommended applications for commercial antibodies
Maybe WB is easier for them to test?

In general, however, my recommendation is to check if they provide refs to paper using those antibodies and look at the images on the paper.

Be careful putting your trust in the supplier's pictures, I have seen obviously photoshopped images on commercial websites.
Also always double-check the referenced papers, as sometimes they don't really use the same product that is sold...

Other than that, in my experience, the recommended application is just that: recommended. The antibody may as well work for other application.
That said, note that there is a rationale for an antibody working for WB and not IHC, for instance: perfusion with fixators such as PFA will change the 3D structure of the target protein and may mask (or reveal) certain epitops, so the antibody may be more or less efficient depending what form of the protein you're dealing with (native, fixed in PFA, fixed in glutaraldehyde, SDS-denaturated etc.)