that's more or less the same answer I got from Mr. Spreadbury last December - after which I lamented here on the Sagittal forum that combining accidentals will not be possible in Dorico (as the Steinberg software is called). While it's true that we won't need a separate symbol for each combination in the font itself, we'll still need to build a potentially ever-growing palette of such symbols inside Dorico. What we want, however, is the possibility to add individual accidental symbols to an existing note on the page: to first input, say,
, and then add
, instead of having to have
in the palette.
Moreover, Dorico will only support EDOs, so JI will have to be handled as a large EDO. They probably haven't solved microtonal playback at all in the first version that comes out this year.