Believe me, you want to know where you will go at any point of time should a 'Land ASAP' event happen.
Don't you have a FMC page for that with list of the closest airports? The 737 has, including info on mileage, fuel remaining at destination and a one click weather request for any thus selected airport.
However being able to enter a time directly as waypoint can be pretty useful, sadly we do not have that.
Apart from that the fix pages are a nice tool for whatever you want, be it to draw nice circles in the middle of nowhere or remind one of a fuel check/reporting point or of course an ETP if you happen to need that (never did on the 737 in europe/northern africa/UAE).