First of all I don't know why such information would be relevant for anyone here and why would any user of this forum need to know how many coins Satoshi has. To my opinion that is privileged information and not something that should be shared in public
I think that information how much Bitcoin Satoshi has will remain unknown as well as true information about his identity.
Well, it's easy to see how this can be important to many people. Even if we don't know the identity of the person (btw I'm honestly tired of how
99% of the time people assume Satoshi is a guy even though
half of humanity is female, not to mention that there are people with other gender identities beyond this opposition), some believe it's possible to make estimations of how many bitcoins Satoshi has. If it's one person or a small group of people, and they own the hell lot of bitcoins (as it's usually assumed), then even without their identities we can know that there's someone out there who can change the market state at any point by simply selling all those coins. It would not help much to know this because nothing can be done about it, but it's a big part of an answer to the question about whether one person or a small group can manipulate the price of Bitcoin.