The annual interest rate is 4.08%.
Yes, you are right. I am Premium tier 3 and confused the base interest rate with the total, though this does not change too much the calculations: interest not earned on the 0.07 BTC becomes 0.002856, extra interest due to maximum premium level would then be 1.02% (25% of 4.08%) and you would still need to earn (0.002856 - 0.001947) / 0.0102 = 0.08911764705.
Anyway, this was a rough estimate assuming ~ideal conditions, which ignores, for instance, that WOF prices have been historically higher (so a person may have invested much more than 0.07 BTC to get them). So a small typo in the base interest does not make the point invalid: you need a large balance for Premium to be worth the cost and not lose money. For that same reason I bought a lower Premium tier and even with that, after about 2 years I am just about to break even and finally start getting a profit.
From accumulating WOF spins I have also noticed that lottery tickets are a bit more common in practice, though not sure if it has been mere bad luck the 3~4 times I have exchanged batches of WOF spins (500~1000 at a time). I won the second lowest prize in the lottery once, so that probably balances things out.
The investment reaches its full potential after the first year. I took the risk, because the site is alive and legit since 2013
This is assuming you have hold your tokens for at least 365 days.
If you purchase 500,000 FUN tokens, you would get 5230 WOF spins in the first year and 5840 WOF spins in the next years.
Yes, my estimate was a rough one not meant to be accurate but to give a general idea. For that same reason I optimistically assumed full benefits (as I stated before). I have also been a long time Freebitco user, but another point was that you need to trust the site long term for the investment to be worth.
That's normal.
The probability of winning in a game with multiplier of 1.01 is 94.06%
This is not "normal", at least in terms of "standard" odds. Any crypto-casino will give you at least 98% odds for a 1.01 multiplier and for 94.06% pay out 1.05+.
Though this is not surprising, it is well known that Freebitco has horrible odds (they need to get from somewhere the money to pay interest), it is up to everyone if they consider dust RP (from flash promos) worth the risk given the very high house edge at this site. I would certainly not roll for 1.01 with a 5.94% chance of losing (i.e. ~6 out of 100 times).