[O] Timestamp, deadline and scheduling clarification

[SW]

I'd like to clarify some of the usage of timestamps. Preceeding a timestamp with
DEADLINE or SCHEDULE gives extra functionality in the agenda. Omitting these
keywords produces a normal timestamp which *appears* in the agenda but does not
trigger advanced warning before and does not continue to remind afterwards -- is
this correct? So such a normal timestamp appears and disappears off the agenda
and could therefore be missed. What is the use-case of a normal timestamp -- one
without DEADLINE or SCHEDULE?