Like, you can still play the game without a SSD....it'll just be a bit more sucky due to hold ups in cinematics.
Again, I don't think this is accurate.
I think they will be mostly fine until they get to Baldur's Gate and then they will bottom out on frame rates and possibly crash.
Look - Let's apply a best case scenario /worst case scenario to your advice and my (and the developer's advice)
My advice:
Best case: Player avoids massive problems when they get to the city, and is able to play the game at normal framerates with no slowdown.
Worst Case: The game plays faster, and they are out $50 for the SSD.
Your Advice:
Best Case: They have a slowdown in frame rates in heavily populated areas but are ultimately able to play. In Baldur's Gate the game slows down a lot but is otherwise OK.
Worst Case: The game is unplayable due to serious slowdown or crashes due to thrashing. Player has to now replace their Storage device with an SSD. This may or may not involve a total re-install of the OS and game (not if they know what they are doing). The whole process takes minimum of a few days, maximum of a couple weeks. Or they get frustrated and stop playing. They are angry and frustrated with the person who gave them the bad advice but don't know your name and are too depressed to look it up. They spend their remaining days an unfulfilled wreck of a human being having never finished BG3.
On their deathbed their last words are "I wish I had upgraded my hard drive..." (Beeeeeeeep)