Wizards hasn't published a “campaign setting” book for the Forgotten Realms for 5th edition. (Yet?) There material scattered through several books — the Sword Coast Adventurer's Guide, plus all the hardcover adventures except Curse of Strahd — but no definitive campaign setting book like we've seen in past years. Information scattered across multiple sources like that, and being only a small fraction of what a campaign setting for the Realms normally covers, makes that an unsatisfactory source.
Until a proper campaign setting is published, there's only the old campaign setting guides to really go from, plus the bits and pieces of updates scattered across various 5e products. Ironically, the fan-maintained wiki is the most up-to-date source for the Realms after the Second Sundering (i.e., the D&D 5th edition era).
Are the SCAG and the adventures worth picking up just for the lore?
If you're looking for setting material, I'd say… probably not the adventures? That would be so much material to sift through for just a few bits of lore. What you'd get would be very detailed for some small parts of the Realms.
The SCAG is a better prospect, as it's closer to being a setting guide. Limited as its geographical scope is, it may be worth it if you intend to adventure mainly on the Sword Coast. (And the Sword Coast is thousands of miles long, so that's not as limited as it could be.) I'd say you should leaf through it if you get a chance to see a physical copy — or look for reviews of SCAG that give you a feel for what it covers and how deeply — and make a decision then.