It's a true statement; I made a usable construct that causes template strings to be turned into objects, rather than to perform the string substitution. I did it without changing any syntax, or have to ship a new version of the language.

Python has to ship a new version for this; there is no way for existing installations to use the code.

I don't have to change anything in my editor setup.

So who is it that values syntactic convention?

t"abc" is a syntax errror in vast numbers of existing Python installations; how can we call it convention?

> How do you assign this result to a variable?

That's to be worked out. The "html:" fantasy construct could have a way to do that. When you think of assigning to a variable, the first thing that comes to mind is "a = b" syntax. But, look, the define construct in Python also assigns to a variable:

  define fun(arg):
    ...

> How is it any better

It renders all of the following problems unrepresentable: mismatched angle brackets, mismatched or unclosed tags, bad attribute syntax, injection.