The Glock 19 is preferable in a service pistol role because of its optics readiness and compatibility with double-stack magazines. However, in a covert position, it's unclear if the longer barrel truly offers the Glock 48 an advantage over the Glock 43X, which has the same grip as the Glock 48.
As an advanced armorer and owner of 30ish Glocks, I can say with absolute authority that the single stack Glocks have ONE advantage over their double stack counterparts - they fit inside the waistband better during that window of time between gaining a few pounds and buying bigger pants!
I have large hands, and I much prefer the grip size of a double stack magazine pistol. So based on that, I have no use for any single stack Glock. Why would I carry a pistol that's more difficult to hold properly with large hands, and carries less ammunition?