It isn't unpopular really. Most of us know that if something happens during the dive the likelihood of help arriving on time for anything more than a recovery may not be very high. But if someone doesn't trigger the recovery on time, there may be nothing to put on your casket.
Also there are many things that could happen on that dive day, not necessarily underwater. Pilots submit flight plans, many boaters do similar with certain marinas too.
My husband and I dive solo taking turns out of our boat, depending on conditions or mood we say how long we are planning to dive.
Not that the person topside is gonna be able to save the day if something fatal happens, but knowing something is not right at a timely manner increases the chances of gear recovery... we don't care about the casket deal.
Typically we stay 1 hour. Sometimes things look really nice, we feel particularly optimistic and there's no topside commitments, so we say I'll be an hour but maybe more, watch for flag signals around the hour mark.