Hittin' stuff. I have one and it's what I grab when I want to bang a paint can closed or knock together some Ikea junk. I use it for "adjusting" woodworking stuff during a glue-up. Basically anything I might use a rubber mallet for, the neon orange dead blow "maraca of death" comes out.
Seriously, they're handy and one of those things you find uses for.
The way I was taught to think of Harbor Freight is to buy a tool you aren't sure you'll need from them. If you use it until it breaks you know that it's something you need/will use and you should spend the money to get a quality version. If you don't use it until it breaks then you're just out a little bit of money.
The trick to harbor freight is being patient and waiting for sales. They are constantly having some sort of sale, it's just different products on rotation. So if you make a list of what you want and then pick things up as they go on sale, you can get some really good deals. ...If you can get out of the store without buying $100 worth of other random stuff.
It's also knowing that some tools don't need to be premium, at all.
The harbor freight parallel claims, for example, are totally adequate. They do everything a parallel clamp needs to do. Yeah, you can get clamps that are undeniably better from other brands, but why do that when you could buy 2-3 times as many HF ones instead? Run a piece of tightly-fitted construction timber up the spin, slather them with paste wax, hammer the nuts so the handle won't come loose, maybe glue a piece of leather or wood to the jaws and it's pretty much as good as anything. To say nothing of mechanically even simpler stuff like a basic spring clamp.
There are also tools that are cheaper to buy from HF than rent for a project. For a DIYer, even if the tool is worse, that's often the better bet since it removes a huge time pressure from your project.
I've had my 19.99 orange angle grinder for over 10yrs, it's not an everyday use tool, but it works. I picked up one of their 14.99 grinders and the flange that the washer behind the disc mates to was damaged, causing the disc to wobble. Used it as a wire wheel only grinder after that.