I must say this is the first time I've been really impressed by a client-side, real-time implementation. The API is simple and I can imagine building something real-time without thinking about the translation from one protocol to another like I would with web-sockets for example. I've never written a line of Elixir, but this is interesting enough for me to try it.
I mean, I already 'bought in' to the ecosystem for many other reasons, but these are / could be huge extra reason because 1) they solve problems I'm facing, and 2) the potential popularity might alleviate the mild nervousness I have about investing so much into what is still a very young and small ecosystem. As it is, I still hesitate to use Elixir/Phoenix with many of my clients.
An alternative to this is [intercooler.js](http://intercoolerjs.org). Not sure if it is quite as powerful or robust (as an Elixir backend) but if you don't have the time or inclination to learn Elixir (which I do think is a cool language, but at this time in my life I really don't have the time to learn), intercooler is a nice alternative!
Also to be clear, if you are already in the Elixir web ecosystem, EEx (Embedded Elixir) templates are what you currently write for regular server HTML rendering. LiveEEx allows you to take those same templates and support the diffing optimizations the post shows off, so labeling it "another kind of markup script" isn't accurate in this context.
On one hand I kind of agree. It's a special syntax, which is one of the reasons why I personally dislike Vue and Angular, etc.
However, pragmatically, it's minimal and all the guts will be in Elixir - where the people probably most interested in LiveView will be spending most of their time anyway. So it's a net win imho.