Nobody had a lock code on the old Razr. What would you be locking? The ability to place a call?
And yeah as others have said, it protected your texts and pictures. The razr already had a camera.
There wasn't any image content, but you certainly don't need images to have messages you want to keep private.
I wouldn't want anyone I know going through any of my private conversations line by line. I don't see how razr 2004 vs iphone 2019 is any different in that regard.
It was less well used in the US where you were charged a relatively exorbitant rate for sending and receiving texts. $.05/SMS + $.25/MMS
This isn't at all true in my experience, perhaps it's an age/generational thing? Personally, everyone that I know that texts today texted just as much back when they had flip phones like the razr