I didn't say (or at least mean) "useless." Certainly not useless - there are lots of other things that rogues can do superbly, including stealth, disarming traps and focused damage. That said, I will confirm that because of knock, in a 2e->3e->3.5e 16 year long campaign where I played a rogue and we had a second rogue NPC, we used the Open Locks skill fewer than 5 times once the PCs topped 4th level. It was useless because Knock was faster and safer. That spell is pretty much the poster child for niche infiltration, in the same way that 3e's divine power makes the cleric a better fighter than the fighter is.
PC: I can't agree with you here about the safe part. Knock never ever disarmed trapped doors, chests etc... Knock only unlocks and we have learned many many times to just let the rogue handle it.
Cleric being a better fighter is subjective and remains that to this day. There are arguments on both sides but nobody has walked away with the victory.
The cleric thing is another example of DM's actually taking the initiative. Nightsticks were something in Libris Mortis and since 3rd edition didn't carry the "everything is core" title then it didn't have to be allowed. Divine Metamagic had gotten the nerf so it would take pretty much every feat you had to do the Persistent Rightous Might, etc.... Which a simple dispel magic would take care of and leave the cleric back to normal and missing a lot Turn Undead attempts.