compounded interest really adds up quickly, and the difference between even 1.4% and 1.5% are extreme. But still, i will not worry, even 0,1% interest is better then 0%.
By the way, the average interest so far is about 1.4% I have calculated that if they keep compounding interest at the same rate (1.4% per day average) that an initial investment of just 0.3 BTC would become over 40 BTC in a year. This is really insane. (also, i did not truncate like they do).
I was wondering how you came up with 1.4% as it wasn't that high in March, then I saw February had to very large returns. (7 days over 3% with one even being 5.9%) A lot of that had to do with GOX. It probably isn't fair to continue to project those types of returns forward as you should expect the returns from this type of trade to taper off over the months.
In March there were only 8 days above 1.4% and the highest was on 2.28%. There were also 10 days below 1%.
So far the April returns have even been more mild.
I would expect the returns will continue to be reduced each month. There could be some wild event that changes that, but in general the trend is towards lower returns.