Good question. There are some minor annoying things about using control CD / vinyl that will hopefully be eliminated with internal mode.

most of the latency is the result of the operating system servicing the USB audio device. The amount of time it takes to process the incoming audio control signal is trivial when compared to the operating system overhead. Scratch LIVE is already tuned and tweaked to minimize latency, so its unlikely that ITCH will be able to improve on the already minimized latency of Scratch LIVE.

Bu there are some other advantages to using a direct controller of control vinyl/CD. For example needle wear, phono/line levels, and cabling are non-issues with itch.

There are other issues you face mixing with Absolute / Relative Mode and vinyl or CD control. Cueing with CD control has that thing where you can't back up after you rewind the timecode track, unless you hit the first cue point a few times, or jump from the 1 to the 2nd to the 1st again. The estimate button you have to calibrate, etc... I'm curious to see what it's like trying to mix on such a small controller. It could make a few gigs easier until itch has bigger controllers to work with. Would be nice if ITCH supported the VCI-100 for now though!