Hi. First of all, nice to see a street rider here. Sorry to tell you though, almost all of the other street/trials/flat riders hang out on Facebook, this forum almost exclusively concerns itself with beginners, distance and “Muni”.
To your question: If you land sideways with a tubeless setup, it can “burp” a lot of air. Especially with non tubeless specific tires (I don’t know of any 19" or 20" ready tires). And with street, you tend to land sideways sometimes. If you want to save some weight, you can use a slim inner tube, but I don’t recommend that, unless you like riding really high tire pressure to not get any flats.
I am new to unicycles but bicycle road riders with fast lightweight bikes and some commuters, etc., like tubeless tires but they run narrow tires with high air pressure and those tires are not likely to see much sidewall deflection, unlike MTB and other offroad bikes.