We would open up ourselves to more litigation risk, by having too many options, the scenario of "it wasn't clear" is a much stronger case when you have multiple and varying options. With just two options it is clear cut.
Time Based Wallets, hoard the coins for an agreed period of time and in return for the protection against negative movements and you get a percentage of any growth.
These "Time Based Wallets" sound interesting. Can you give more info about them? Also isn't this like a 3rd option?
Will the 100% pegged accounts provide any interest rate? You will be competing with banks that offer decent interest rates even on simple accounts who don't commit to a time deposit. Say you customers give 10% exposure to Bitcoin even on 100% pegged accounts. You could easily take up the risk and still offer customers a decent interest rate.