It's a different thing. In this thread, we're not discussing the unique abilities of a Rogue(Assassin), but rather the general idea (usable by anyone) of hiding before attacking.
Of course hiding before attacking is much better if you have Sneak Attack (any Rogue), but anyone can do that and get advantage at least.
A secondary topic of the OP was what happens if you need only dim-light to hide, for example if you have the Stealth feat.
The Assassin's unique ability is a different thing, indeed it's better, that's why you need to be a more specific (and specialized) character to have it![]()
Well, I wouldn't worry about the whole hiding in dim light thing, because it sounded like they were getting rid of "dim light vision." We may see the whole dim light mechanic disappear.