Why should we deal with the grounding loop in PCB wiring?

First of all, GND is the reference potential of the whole system, that is, "zero potential", so if GND is not handled well, all your sampling results will not be accurate, resulting in instability of your system, which is reflected in inaccurate analog sampling; Reflected in the digital quantity, change to 1 is 0;

Secondly, GND is the leakage loop of all interference, so GND has determined many test levels in EMC test. GND is not good, static electricity is not easy to pass, surge is not easy to discharge current, and it is easy to radiate.

Therefore, if the GND layout is reasonable, the system will be more stable.

The above is my understanding, I hope it will help you.