tr -d '0-9' removes ASCII digits. The removal itself is trivial; the state it leaves the text in is where the work is.
Collapsing what is left
Removing digits from /product/12345/reviews gives /product//reviews with an empty path segment. For pattern grouping, replace runs of digits with a single placeholder token instead of deleting them — /product/{id}/reviews is both readable and unambiguous, where the deleted version could collide with a genuinely different path.
Unicode digits again
tr -d '0-9' misses Devanagari, Arabic-Indic and full-width numerals. A Unicode-aware \p{Nd} covers the numeric decimal category properly.
Digits inside words
utf8, h1 and covid19 lose meaning when stripped. If the goal is normalising identifiers rather than removing all numbers, target digit runs at path-segment boundaries specifically rather than every digit in the string — the broader rule destroys tokens you needed.
Try it: Strip Digits from Text on SeoWolf's Notepad.