The primary purpose for this is to get the footnotes to have proper margins. For example,
will produce a footnote that goes well beyond the boundary of the table. Alternatively, one could add
\centeringinside the minipage, which would mean the footnote underruns both sides of the table. The only way I know of to do this "naturally" (i.e., with
\footnoteand without using packages like threeparttable that require a bit more manual control of things) is to manually set the width to the width of the table (which of course requires tweaking when the table's content changes).
With the new environment, the footnotes are always exactly the same as the width of the table itself (at least, they are after the second and subsequent runs). One can then apply centering (etc.) to the table, including footnotes, as a whole, which is typically what is desired. The result using the example above with this new environment (which I call "mptabular" for obvious reasons) produces the equivalent of
Except that the user does not have to explicitly enter (or know) the width of the minipage.
The question I have is this: would this package be of interest to the community? If so, is it a duplication of something already out there, or does this functionality not yet exist?