I'm sure most know this but if anyone thinks this is a way of doing forensics, keep in mind it can be easily skipped over by doing a non-standard logout, like "kill -9 $$" or if a remote ssh connection gets cut for whatever reason. The command history for a session won't get written until logout by default. A workaround such as forcing each entry to be written to a log file will have to be done to have better assurance of true history.
Excellent point. Seeing when a command in the history list was run is very useful.
My preference is just for a date in the history, rather than date and time. I find that when I'm searching history, date is usually granular enough for me, so I can omit the time and save a little bit of screen real estate.