I don't think this prediction is negative though. It could attract investors searching a safe store of value, for the first time, if even a conservative bank predicts a ROI way above inflation.
Thanks for the computation, which proves that their prediction is just conservative, and I think that's really how banks operate.
For instance, if we take out a loan and put up collateral, they usually give us 50% or even less of its value.
So the same goes with bitcoin, to be on the safe side they made a conservative prediction, and that long-term 10% return is already better than what many other types of investments offer, therefore the risk now is how to secure our bitcoin since the rate of different scams in crypto is still high.