Hi - I'm so new here that my skin is still wet :-). Here's how I see it. If we put our funds into the PS, and let it build to a point where a weekly w/d will cover our living expenses (NOT an overnight job from what I have seen so far) we would most likely be WAY better off than any bank or mutual fund.
I watched a video stating that Steem has an increase element to it. Said that Steem Dollars would accrue about 10% a year and the other 90% of the doubling of the amount of steem created would be distributed among the members who have S/P in their wallets. He gave the impression that the s/p built at 90% per year. so 100K this year = 190K next year. At the present exchange rate, we will find that there is a percentage of S/P we can take every week and still have the balance grow so it will always be there.

After all, this is exactly what we do when we invest in a mutual fund. Build up a supply until there is enough to live on - JUST from interest.
Great reason to add as much as you can early to the SP account.