This is neat, but I wish there were more examples than just a counter. I would never use something like Angular, React, or Vue to implement something so trivial.
Also if you're in a React project, yes, you would use it for a counter. Obviously you wouldn't use React for just a counter, but it's a great way to show the basics of working with each option.
You probably shouldn't, but there are a lot of people who reach for a React component to do anything on the web.
One reason is obviously that writing something in 30+ different framework that you need to "learn" is quite some work :) (10x more that I initially thought :D)
The other reason is that a simple component actually amplify the cost of the framework. And if you think about it, with a more complex component, what you have is more HTML, more CSS and more JS but they are essentially always the same. Only the binding are different from one framework to another. So in the end, the counter is actually a good representation of the cost related to the technology.
This been said, to be correct, the benchmark component should use more capabilities like slots and events to really cover the wide range of capabilities.
This is something we have in mind for a future update of the blog post...
Ah, this is where you can use the Internet to your advantage. If you ask for help in advance, you generally won't get it, but if you post something broken or dodgy people will come out of the woodwork to correct you. So you don't need to work so hard to be correct. Just post something. Anything.
If that still isn't enough for some particular framework, just post something less than entirely complimentary about it ("I'm not entirely sure this framework is the best thing since sliced bread") and you'll be sure to get support, with a side helping of flamewar impugnment of your motives, intelligence, and ancestry, along with pithy observations about your obvious inability to recognize sliced bread if it was placed directly on your face. If you can ignore the latter you can get a lot of cross-framework comparisons done with surprisingly little effort on your part.
But then, this is a great part about web components: you can implement a single component however you want, including with no dependencies, and still use it like you would have if you built it with a full-featured library. You can use it in Angular or React even.