I looked at WOF spins primarily, as that's what I see as the biggest perk of the program. The extra interest doesn't amount to much by comparison. Here's what I calculated:
At 5000 Fun tokens, the cost is currently 500k sats (it was more when I did my initial calcs too). After a month you get 3 extra WOF spins and it scales up to 6 daily WOF spins after a year. For the sake of simplicity, I'm just going to calculate 6 extra WOF spins from the start. WOF spins are generally worth 50 sats. Either you get 50 sats or 50 rp which given enough time you can convert to 50 sats if you make it to 100k rp. Sometimes you get more sats on a spin, but sometimes you get lottery tickets too which in all likelihood translate to 0. So expecting 50 sats per spin is reasonable and I would say necessary when you're calculating time to recover investment.
At 6 extra spins a day, you're looking at 300 sats as the extra perk. On a 500k sat investment cost, that's 1667 days, or 4.56 years. And that's only if FUN holds the value you bought it at. Taken that as a given, it's not a compelling investment given the risks. I think you can get more perks at much higher investment costs, but honestly, that's even more risky in my view, so I calculated on what seemed like a reasonable test tier.
Happy to hear any input on where you think I've made an error in logic or if I'm missing something about the program.
You are assuming that the odds of winning 5000 sats are 0% but it is above 1%. At 6 spins per day you should win 5000 sats more than 20 times in a year. That's 100k sats and 100k reward points in a year. There will also be smaller prizes that could give you another 100k sats and 100k reward points per year. Plus, you'd also be getting interest on sats you otherwise wouldn't have.
As I said, it was very rough math done quickly to get in the ballpark of what the return on investment is. But let's correct a couple errors in your logic. First, you're deducting sats from your account to buy FUN, so you're not making any extra interest until the purchase price of FUN has been fully recovered. In fact, you're making less interest until that point, so that's an additional cost of FUN that has to be taken into account when calculating break even.
Second, your expectation to win twenty 5k sat prizes on 1% probability in a year on 2190 spins is overblown. You have to use a binomial probability equation to solve this. Saving the hardcore math and just using a calculator for this, the odds of winning at least twenty 5k prizes in 2190 spins is only 68.7%. Expecting 100k in earnings is not a safe assumption.
Under the best circumstances, the end result is still multi-year repayment period on an alt coin that will probably not hold its value it attains during this pump and which most people buy in at.
Reading this really opened my mind to the opportunity cost of buying fun tokens in that the sats spent will no longer be earning interest directly,
However it also made me realise that since the average daily reward for fun tokens membership level 1 is approx 50 sats through the initial 1 free WOF but in the form of rp, lottery tickets or sats itself,
if one where to then calculate the amount to get the first premium membership of 2500 fun tokens which is about 0.0011btc with fun being at a price of 44 sats per one.
it can therefore be estimated that your daily 4.08apy interest on that 0.0011btc would ideally be just 12 sats, On the contrary if that btc was used to purchase fun tokens your daily interest would technically be increased to 50 sats as per that being the average wof reward and 1 is instantly awarded after just one day of purchasing and holding the 2500 fun tokens