Back when I was studying the Double Entry (DE) system felt like "why why why?" because it felt like an overly-complicated way of performing transaction and storing financial records. But now I feel like it's something that can't be missing.
Also take in mind that Double Entry was invented 400 years before computers. However even with computers, it's still useful for its properties of guaranteeing transactions make sense.
The best way to explain it from a programmer perspective is CRC and Error Check Codes.
Imagine we had to store a value in ECC RAM, but we have to manually calculate the ECC bits.
For the sake of simplicity I'm going to deviate a bit from how real RAM works, and assume the following: