Building a 3D printer is easy. Getting the details right to build a great 3D printer is hard, as this is where most companies fail. Why?
For example, on this printer, the bed is a three-point mount (two wheels for adjustment at the front of the printbed) and the printer's bed levelling dialogue doesn't show the height difference that needs to be adjusted (which most 3D printers do). It does show how much it needs to be turned, and the bed levelling wheels have 1/8th turn indicators, making it easy to get it perfect.
In short, instead of an arbitrary number like 0.3mm that has no meaning to the user, they tell the user to turn this knob 1/4 of a turn. An instruction the user can follow.
** Why is this so outstanding? It doesn't cost much, but it improves the user experience. Are companies blind to these improvements because the engineers are experienced, or is there a lack of testing during development?**
By the way, years ago I did such a fix/modification myself on a Tronxy XY2 pro by adding indicators on the wheel for 0.2mm height difference so I could convert the number to rotation: https://www.printables.com/model/301670-replacement-bed-leveling-wheel
You should still have a roughly level bed, even with abl. It's not meant to make up for a massively skewed bed, is and that will affect print quality if you ignore it.
I prefer a fully rigid mounted bed without these cursed springs. It either gets leveled once with shims, it the printer can adjust it's x-y-plane to be coplanar with the bed (or adjust the whole bed to the x-y-plane). And yes it might need abl to compensate for thermal expansion, but not for small enough printers for example.
+1 on shim levelled bed. At least with a klicky probe and skew calibration which I already had before shimming, the supposed heat warpage related issues have not shown up for me. Maybe its more noticeable on different mounting methods.