It's an argument as to what is a bot or fake account. Elon is saying that any account that isn't a unique user (only one account per IP) is fake/bot. Twitter is saying bots/fake accounts are only those that are automated. So when Elon says he thinks fake acounts are upwards of 70% he might be close but at the same time Twitter saying it's less then 5% could be close too. Just depends on how you classify bot/fake accounts. Going by the accepted definition of a bot account twitter is probably more correct but in the end Elon has never just been about bots he's wanted to know the actual ammount of unique users. It looks like the court is ultimately going to decide. Remember to though that Twitter has already been caught, twice, misrepresenting numbers.
The majority of people I know have 2-3 accounts some more. My guess is the amount of actual unique users is roughly 35-40ish percent of what Twitter claims.
I think Elon is playing a game with Twitter. Getting sued and counter sueing will make a whole lot of information twitter doesn't out available to the public. If twitter balks at giving up the info that very well could be the final posion pill for the company as we know it. On the other hand I doubt Elon would put his reputation on the line if he didn't know something.