i think the dsp part of theses rme devices is mostly usefull for FOH, and then the low latency and the good a/d are mostly usefull for recording / composing / mixing. the device stability itself is usefull for everything.
that's just a thought and the way i use my rme device...
i mean when using ableton ou pt, i complety forget about TMFX and dsp.
when recording in live or pt, i use the TMFX features, such as gain setting or auto level, and also general routing (monitoring, headphones routing). i don't use dsp since i can (later) put some eq/com/verb in a virtual way with plug ins.
but for FOH, quasi zero latency dsp eq/comp/verb can be so ussefull, aren't they ?