I never really understood why anyone thinks this is a good idea. Popular, maybe. Smart? Not so sure.

Instead of just modifying your parser, you change your entire input format to be incompatible with what most of the rest of the world uses (standard JSON).

I get it, it requires slightly more technical skill / effort / etc to implement a proper streaming JSON parser (which BTW will perform WAY better in terms of speed and memory) instead of just writing "my_data.split('\n')". But, there are pre-existing libraries that already do that, and a one-time tiny bit of extra work, to open up a capability that you can reuse anywhere in your stack, seems to be a much better option than a lifetime of incompatibility with standard JSON.