Yes. Change of paradigm does require change of tooling. If some legacy tool doesn’t support new format, it’s not a good reason not to use new technology - either tool evolves or a replacement emerges and typing won’t be a problem. Classic formatting commands from rich text (Ctrl-B etc) can be repurposed, for example.

>Also, what is the difference between using some new character to start block and "{" or "\n"?

Any such delimiter has other use in text. Dual use means extra ceremony with escaping and extra complexity. Whitespace as a delimiter has especially bad UX, because most editors don’t understand the semantics and it is very to make mistakes.