Am Di., 23. Apr. 2019 um 17:51 Uhr schrieb Alex Shinn <xxxxxx@gmail.com>:
>
> What do we gain?

Everything. :) The only thing we don't get is that *user*-predefined
variables cannot be used with the SRFI 166 formatters. (But the same
holds for the current implementation where the set of predefined
environment variables is fixed.)

In particular, all procedures that combine monadic procedures and
values in SRFI 165 do not care about how the environment has been
created. The caveat only applies to the predefined environment
variables.