Things on the Internet are either free or out of reach.

The problem with free is that free things tend to be abused.

I've asked myself: are there any queries that I could perform on HiveSQL that would be worth the $40 a month subscription. So, the sad truth is "No"

IMHO, HIVE would be a happier and more sustainable ecosystem if we had more middle ground structures that minnows and dolphins could afford. I don't think you have to aim at making HIVEsql free. There needs to be some ways for low value accounts to small amounts of computer time on the machine to make periodic queries.