It can be applied to digital goods, physical good, or processes.
There is definitely a limitation, however, in that some programs really emphasize what Don Norman calls “pixel twiddling”. If the educational background is really hyper-focused on the interface design portion, sometimes the translation to other processes is a bit harder.
However, there does seem to be a constant push within the field to keep from defining UX as the design of interfaces. This is partially shown in the increase of distinction between UX Designers and UX Researchers, but many organizations don’t really understand or discriminate between the two.
For the record, that distinction is one of the things that’s driving my job search. As an engineer, I’m not nearly as competitive in purely software side of things, trained in analysis and experimentation, not design.