radio-group, checkbox-group, select: Specify value via  field in BEMJSO...

...N #1055
I can't say I believe that [my calculations][1] are valid, but as with rendering time, I couldn't get any visible difference :( Both versions consume the same amount of memory: about 39Mb on my laptop.

[1]: https://github.com/bem/bem-components/compare/issues/1055%40v2...issues/1055-bench%40v2#diff-bf2f25928a0b46d29e7743d11b05f999R29