Personally, I have been trying to determine if I should buy or build a new mobile game backend that has an average of 50-250K iPhone app downloads/month. I'm adding online multiplayer to an otherwise single-player game.
I've looked at Firebase and a number of other offerings include Exit Games' Photon Cloud. Firebase had seemed to be expensive for my use case of ~ 400K MAU. However, Firebase's experience of 1 CCU = ~ 1400 MAU [1] would be easily supported under the "Candle" or "Bonfire" tiers which are not expensive.
Exit Games' has a different experience [2] but I'm probably comparing apples to oranges a bit. Games vs Big Brother. Well, there is Roll20 so maybe it's at least comparable experiences.
1 CCU = 1400 MAU vs 1 CCU = 20 MAU
That's a big difference. Am I thinking about this strangely?
[1] "In our experience, 1 concurrent corresponds to roughly 1,400 monthly visits." https://www.firebase.com/pricing.html#pricing-faq
[2] "To calculate monthly active users (MAU) we assume a CCU to translate into 10 daily active users (DAU) and each of these into 20 MAU" https://cloud.exitgames.com/Pricing