For that comparison yes it needs to be just a date field.
You could go by just date but then this may not do exactly 24 hours. Say a person entered a record at night today and then went to the report tomorrow, if you just go by the date and not the time then that record would be checked the next day even if it was only about 12 hours away. If that is okay then this would work.
Either way this is the way I would personally attack this. This ensures it is 24 hours after the fact and no sooner. This assumes [Sent to Sales] is Date/Time.
if(
Now() - [Sent to Sales] > Hours(24), true
)