I just tried it on an initrd. It obviously calls other utilities, not replace them (e.g. cpio, tar). And gunzipped the files in /lib/modules the way I used it.
This utility has very few options, hence make a lot of assumptions. My advice: if you really want to use it, do that with extreme care. Personally I'll continue to use directly other utilities that have a lot more flexibility and are able to make archives, not just extract/expand them.
There can be some specific use cases where dtrx is useful however, but using it just to save some typing is not worthwhile as you still need to understand underlying utilities' options.
That's only MHO, of course
