Generating gerber and drill files for manufacturing is pretty straightforward in Kicad, but getting boards assembled with JLCPCB is a lot more annoying --- you

Generating gerber and drill files for manufacturing is pretty straightforward in Kicad, but getting boards assembled with JLCPCB is a lot more annoying --- you need to associate LCSC (JLCPCB's supplier/sister company) part numbers with each component, and generate pick and place files. And inevitably you won't be able to get certain components from JLCPCB so you'll end up buying those separately and hand-soldering them anyway, so it can feel like it isn't worth all the hassle. For simple one-off boards it's easiest to do that association in the JLCPCB order flow instead of in Kicad. I agree, it's a lot less slick than the EasyEDA/JLCPCB integration, so for people just getting started with PCB design I would definitely recommend EasyEDA over Kicad.