A screenshot is considered far more trustworthy by non-tech people than "I spoke to Fred and would you believe it, he told me X and Y were doing Z behind the bike sheds!!!"
Someone saying something about what they talked about does not. You can say one thing today and another tomorrow.
This is why the written word has magic that the spoken word does not. And the longer the append-only chain of written words goes, the more magic it has.
The evidence submitted with the legal case was a cell phone with the messages app open ... and it appeared to be photocopied. Then they scrolled up ... another photocopy, and on and on and on.
Granted further investigation can be done, but it was amusing to see.
They were arguing about what color to paint them! How scandalous!!!
Cryptography sometimes seem to rely on a stronger version this too. With enough computing power, you can brute force a lot. Some authentication seems just expensive enough that only a nation-state actor would have enough resources to break it, and then rests on the assumption that the small subset of people who could put in enough effort won't care enough to do anything worth being concerned about.
This is also why, say, people lock their doors even if they have windows.