I've recently realized that, due to how \newenvironment, \begin, and \end work, there is no reason you can't have environment names with spaces in them.
As long as you stick with \begin and \end, this works.
So, why do environment names always consist of catcode 11 characters?
Why is the ability to use \env and \endenv (easily) so important?
(If you're making your own environment that needs these, it's peanuts to use \csname my env\endcsname.)
Is it simply bad style?
To clear any possible confusion, why is
\newenvironment{somename}
preferable to
\newenvironment{some name}
at the document level?
tabularxwas actually calledtabular x, when you considertabularxinside a\newenvironment? Here you require the command-form\tabularx...\endtabularx, which is far easier (more convenient) than\csname tabular x\endcsname...\csname endtabular x\endcsname`. – Werner Aug 14 '13 at 02:09