Great question, trouble is I am not sure if I am good enough to really quantify the difference
. I saw the same video you did as well and also at the time of the B44.1 release everyone seemed to be raving about BB spring conversions. In addition when the K1 came out Schumacher changed from full BB setup to a small bore/BB spring combo so I changed to SB/BB spring then and it felt good indoor and outdoor. When I changed to Losi full BB setup I could not tell the difference indoors but saw a change on bumpy astro with much better jump landing and rapid bump handling.
That said I mainly use them as I have 4 cars (mine and sons) with either full BB or SB/BB springs and they all use the same Losi BB springs so it is convenience mainly.