It isnt sarcasm. I don't really find a case that a database that has it's own query language like SQL is needed. It won't be different than storing a JSON file and filter the content with a for loop, the dev (e.g. me) will be returning a JSON on REST API at the end. A query language may be a good thing if you are working in a team, thats it. SQL is indeed isnt a good thing.
Um, so your use cases are extremely narrow and limited. That's an astonising failure of imagination and a lack of understanding of real-world computer systems if you cannot understand why people have a real need of both the power of SQL and the performance of RDBMSs.
PostGIS is an extension of PostgreSQL. It claims that it has some geography features. I think it is not really related with a database. It brings only a function (HAVERSINE) that gets distance of two points on earth. It is couple of lines of code. It is not really a software project, but a detail about how the earth coordinates are calculated, and I think it is a total made up story. The real computed thing works like math.sqrt function.
I worked as a software engineer for 30 years before being forced to use a database, and that was for a web site. I've been coding actively, daily, since the 70's. Forever we just wrote proprietary files to disk, and that was the norm, for decades. Many a new developer can't even imagine writing their own proprietary file formats, the idea literally scares them. The engineers produced today are a shadow of what they used to be.