There is a little nuance with that stat. It is not "80% are on mobile", it is "80% log into Roblox with mobile devices".
Can be a huge difference or not, but as Roblox is one account for all devices, it is quite unlikely that only 17% play on PC and 3% on console (the other stats)
Also, we can infer that either not many use it as their primary way to play, or actively avoid paying on mobile, because only 46% of revenue is generated on Mobile. (or that 20% of Roblox users generate 54% of total revenue, which is unlikely)
The stat is either the account creation device, or the most hours logged into the device. The full stat is reaching 100% so they don't account for multiple devices
The reality is likely that Mobile is a companion app.
Roblox reached 82.9 million daily active users in 2024, 80% of whom played on mobile.
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