@aral six months ago I would have agreed completely. And I still do for anything that goes into production, or is to be used by anyone but myself. But single use little apps has become my best friend...
I work a lot with databases at the moment, and one of the most hellish things is to switch modes (mentally) between automatic sorting using regex and whatnot, manual tweaking to things that don't get caught by regex and others scripts, different data views to see what's going on where, etc.
By vibe coding small Textual apps, using code I could never write or maintain myself, I can read from a live database, and write to a live database. The app can do any changes I want, using any keyboard shortcuts I want.
So when I inspect entries in a database, and "oh crap there are a hundred mangled replicas of the same entry here, but no columns are the same!!" - instead of spending 20 minutes figuring out how a script can detect duplicate content across different columns, I can spend 3 minutes vibing a new version of my app, that is basically just Tinder for databases. Right arrow = keep, left arrow = discard, up arrow = good data. I can now sort 100 entries in less than a minute.
I would never claim the app is good, I would never sell it, heck I probably wouldn't even give it to anyone because it would as you rightly say be hell (or impossible) to maintain or improve. It crashes sometimes, but it doesn't matter because it writes directly to db, so all changes are saved.
There *are* things AI can be used for, that involve a clueless monkey just asking it to do things. Like write good SEO metadata for a website. Like looking through a complicated repo and giving me different sorts of maps and flowcharts depending on what I need to look for and understand. Like reading a 40mb plain text file and finding out what sort of CSV it originally was supposed to be, before someone gabled it through 15 different encodings. In that last example, I would never of course use LLMs to recreate the data structure (slow, unnecessary use of energy, lots and lots of errors, etc). But having a machine tell me the structure, visually in a TUI, so I can get the regex right the fourteenth time instead of the 140th time, dude I'm here for it.