I had a reply, but I lost it due to session shenanigans, and I don't want to write it all again.
But for RSS applications: considering they already have more than 14000 Twitter recipes, supporting IFTTT seems an excellent reason for implementing RSS. Particularly since it should take a few dozen lines of code, if that, in any decent language.
I don't see the point in this trying to be everything to everyone sort of deal.