Why Last-login?

[@lbutlr]

I've noticed several threads over the last year or so about last-login, and I was curious WHY people care about tracking this in the database. I can see wanting to know if a user has logged in recently, but this seems quite easy to tell by simply looking at the time stamp and/or contents of the mail spool for the user.

For example, on my system I can look at the timestamps on the 'new' folders in the user's maildir to see if they are getting mail, and if the folders are empty, I have a time stamp of when they last checked that mailbox, giving me a pretty accurate time for when they last logged in.

For example, looking at one user:

 # ls -lsdtr /path/to/user/maildir/{new,.**/new} 

I can see that the most recent "new" mailboxes were accessed on 02 Mar 14:25 and 03 Mar 01:45, and I can see that the latter mailbox has files in it and the former mailbox does not (just by the size, without doing an extra ls of those directories), so I know that the last time the user logged in was about 14:25 or later yesterday and that they definitely have not logged in in the last 3h05, which seems close enough to me.

Am I missing some reason I would need/want to keep track of that specific login time separately?

-- 
'But you ain't part of it, are you?' said Granny conversationally.
	'You try, but you always find yourself watchin' yourself watchin'
	people, eh? Never quite believin' anything? Thinkin' the wrong
	thoughts?'