I mean, this just appears to be fixed nominal returns, minus a fee, multiplied by a factor from an actuarial table.

Contrast it with a calculator like this [0] that uses combines historical return and inflation data with actuarial data to show the variance of outcomes, not just average returns.

For instance, your calculator shows a scenario of investing in bitcoin and withdrawing >20% of your portfolio every year which makes zero sense once you account for variance of returns.

I like the idea of tontines, I'm glad someone is trying to bring them back, and I don't doubt that your product could help with longevity risk, but I haven't seen anything so far that actually shows that.

I'd like to see actual results from backtesting, or a prediction that takes risk into account, not just a fixed return.

[0]https://engaging-data.com/will-money-last-retire-early/