It remembers
An auction sits live for a week. A watcher without a memory finds the
same thing every hour and mails it to you every hour, and you mute it on
day two. Everything found is written down first, so a thing is reported
once and never again.
It filters
One brand name alone returned 112 results, among them cologne, a
blouse and an aftershave. A price floor and a list of words that rule a
thing out are the difference between a tool you keep and one you turn
off.
It counts the real price
On a seven dollar item the shipping is most of the cost. Every find
carries the landed price, so a cheap thing with brutal postage never
reads as a deal.
It stops
Nothing is bought, bid on, signed or sent on your behalf. It watches
and it tells you. Anything that costs money or is hard to undo waits for
a person, and that is the feature rather than the limitation.