I for my part consider numbers like “1234567890” a lot harder to read than “$1234567890$”. And the different appearance between numbers in prose and numbers in $\LaTeX$ formulas looks somewhat inconsistent. Furthermore, the non-lining “0” is a lot easier to mistake for a letter “o” than the lining “$0$” for “O”.
On the whole it seems to me that the use of these numerals does look interesting and beautiful at first glance, but is rather annoying in actually reading these posts. As a consequence I tend to write all figures as $\LaTeX$ formulas in my posts. But this, too, feels wrong: either there is a deliberate and community-supported design decision that text figures should be used, in which case I shouldn't go against that decision without more reason. Or the way I avoid text figures is preferred, in which case this should be the default as well, to avoid the overhead of dolar signs all over your post as well as to allow newcomers to write nicely styled texts without having to know about formula syntax.
Edit: Thanks to the comment by @40 votes I now realize that the Georgia font does not contain lining figures, so switching this aspect of the design would not simply be a change to some config setting, but a change in the font used throughout the page, with everything that entails. The concerns voiced above may even warrant such a radical change, though.