IME, modern compact road frames were an attempt to use marketspeak to justify a smaller run of frame sizes. After a year or two it became apparent that mfrs needed more than just 3 or 4 frame sizes regardless of top tube angle. At that point it was too late to abandon the marketspeak justification for the new/improved design, so they kept on keeping on with the marketspeak and just as many different frame sizes. I'm talking about the modern inception of this design, now 20yrs ago.

To be fair, in our current world of exploring gravel/sketchy surfaces at speed, and many of us enthusiasts aging, it's not a bad thing to have a frame with generous standover clearance that can still get handlebars up into our aged comfort zone.

I speak only for myself, though. And I stubbornly insist on the Swinging Leg Mount, so a sloped top tube doesn't make it any easier for me to get on/off the bike. I'm sure that will change as my hip sockets disintegrate further.