If you enable SSA without VIOT from the wiki then you get to browse the playlists by voice but searching by artist, genre, etc. you would need to buy VIOT.
All my music was on CD so when I transferred this to the DMS I gave every artist their own playlist & use a Kenwood steering wheel remote to navigate to the artist playlist by voice & then read the text on the headunit for the track .
I found myself using this set up with the Audi headunit even though I had full searching by artist, genre, etc. so in my case I don’t think the additional features of VIOT would be worth the extra cost. However if every artist did not have their own playlist I would buy it as long as I could get it to work.