to put that another way why is a backtick (matches \w) deemed more
wordy than a quote which doesn't match \w.

You cross posted to the wrong lists really, regex syntax is as defined
by schema, not by xsl or xquery, and that defines \w as

[#x0000-#x10FFFF]-[\p{P}\p{Z}\p{C}] (all characters except the set of
"punctuation", "separator" and "other" characters)

By backtick I assume you mean U+0060 [`] which isn't a quotation mark,
it's a grave accent and has unicode class Sk so isn't punctuation,
separator or other. (Sk is "symbols")