Sometimes a tool has been invented to do X but people end up using it for Y because it’s so useful. I think "!important" is a good example. Like duct tape being used for much more than attaching ducts.
The ironic thing here is that traditional duct tape should _not_ be used for attaching HVAC ducts together. The adhesive doesn't withstand the temperature extremes, and it has undesirable properties if it catches on fire. UL-listed foil tapes are used for this instead.
It seems like cloth-backed tape started as "duck" tape (as in duck cloth), somehow turned into "duct" tape, and then turned back to "duck" for marketing purposes. It has quite an odd history.
