[kakali]

They don't advertise it as a general programming language. The end of the video they specifically state it only works with optimizing algorithms that deal with images. General stuff like trees, they have no application towards.

[zalman]

The general domain of applicability is data parallel processing. There is very little that is image specific in Halide. So audio, dense linear algebra, some finite element applications, etc. would also be well within the domain.