One nit I'd point out is that's it's always best practice to put the pin 1 dot/label outside the footprint for the part. That way anyone else who looks at the board will have a much easier time understanding the layout and if a component was placed incorrectly.
People use it because it's very cheap, good enough, and they have other services (assembly, association with LCSC that make it even more compelling).
In the US, OSHPark's boards are definitely better quality, but you can't beat the JLC price.
I was recently in a situation where I wanted to fit a new MCU/breakout into an existing PCB designed for a different one. I figured if I liked the results, I could redesign the PCB for a 100% conversion later, but I already had the old boards.
While some of the pinout differences could be papered over in the software, the physical fitment seemed like it would be a tangle of bodge wires or maybe trying to use ribbon cables to tack everything together.
Then I realized PCBs were an option. I could put all the cross-wiring on a PCB about half the size of a baseball card, fab a stack of them for $10 delivered, and have a product that's clean and reliable enough to use without worry.
Throw a design together, have it show up a week or so later, solder it together, do some testing, reorder if you goofed up too much or bodge wire the ones you did order (a component I used neglected to mention one of its output was open-collector...)
Admittedly, it does feel a bit wasteful to order 5 of something that is going to be a one-off. Problem is, ordering all the little SMT adapters modern components need and protoboarding it usually costs the same...
Examples:
https://github.com/teknoman117/P80C550-EVN
https://github.com/teknoman117/M68K-BUS-VOLTAGE-CONVERTER