Don't try to pass on mis-information like its holy grail advice.
FF, what? FF 645? FF 35mm? FF 6x6? FF 6x7?
The term does not even represent 35mm format but any format that is not a crop of the original sensor/film.
A format is just that. No right or wrong. Just because 35mm format on film proceeded the APS-C format prevalent on digital does not mean it is unquestionably better.
Ever seen the macros taken by the folks using u4/3 or compact cameras + macro attachments in the Macro sub-section? The higher DOF can come as an advantage.
High DOF at fast apertures (ie. f2)? High DOF for hyperfocal distance street/candid shots? Yes, all very nicely achieved by a smaller sensor camera.
The photographer simply selects the right tool and format to make life easier (as he/she sees it) for the photography he/she does.
No, he/she should be drawing on limestone caves with powdered pigments