I don't mind repeating that the only guitar to midi converter worth plugging into is the Axon Neural Net.
Yes- the pickup is just the front end and won't output a MIDI signal. The "box" it connects to will.
Some have wavetable synths integrated into the box.
So those have both MIDI out and audio out.
Sure- it costs >VG-88 ($1K) but it works much better. The pickup is under $200- uses its own or
the GK-2A from Roland. Roland's cheaper entry doesn't cut it. The Lyrrus is pretty much a worthless toy. It has to do with the way the processor decodes the frequency that each string is vibrating at from the 6 GK-2A signals. It needs to be able to determine the frequency both quickly and accurately. The non-Axon models trade away accuracy for speed and they're still slower than the Axon.
The latency (how fast a MIDI note on message is sent after a note is struck) varies among the entries in this market from noticeable to unworkable.
No point is spending money on unworkable.
I don't own one (yet!) not because I'm waiting for the price of this technology to drop (it hasn't, which IMHO says volumes all by itself) but simply because my general studio expenses have bled me dry for the moment.
But I did get my SG dialed in by the local guitar Doctor in preparation for its use in this capacity. An axe with all the notes "in" is a necessity for this application.
Santa- Are you listening?