COBOL is easy.
Easy to learn
Easy to program with
Easy to read.
It is very simple. Which is both a strength and its biggest weakness.
The problem is that programs written are NOT structured except the way the guy who wrote the code thought it should be ... if he even thought about it at all.
I was once upon a time hired to convert a COBOL programmed system into an SQL database. The example I use is there was this one proceedure done in COBOL ( take data, modify it this way, output accordingly), literally the same process, but it wasn't a procedure it was coded three different ways. The inputs and outputs should have been the same, they were .... most of the time. And that is why there was this other bit of code checking outputs over there ---->
Also written different ways.
Diarrhea code. They never did get it migrated. The guys who wrote it died and the system died with him. The real fix would have been to have a clean room implementation with three teams, the COBOL team, the API team and the SQL team. But it was a mom and pop shop, and didn't have the funds available which is why the system died when the last of the COBOL coders died.