I think it's more like "I'm not familiar with it and getting it to do something that seems like it should be easy is surprisingly hard, even though I'm putting in some effort." I've become pretty good at jq lately, but for several years before that I would occasionally have some problem that I knew jq could solve, and resolved to sit down and learn the damn thing already, and every time, found it surprisingly difficult. Until you get a really good understanding of it (and good techniques for debugging your expressions), it's often easier just to write a python script.
I love jq, and without detracting from it, gron looks like an extremely useful, "less difficult" complement to it.
Adding: in fact, gron's simplicity is downright inspired. It looks like all it does is convert your json blob into a bunch of assignment statements that have the full path from root to node, and the ability to parse that back into an object. Not sure why I didn't think of that intermediate form being way more greppable. Kudos to the author.
Just as an example, this just took me about a minute to get the data I wanted, whereas I probably spent a half an hour on it yesterday with jq:
I love jq, and without detracting from it, gron looks like an extremely useful, "less difficult" complement to it.