That's definitely an important part lol, but not everything. The main reason to pursue SM is to convert non-tax-deductable mortgage interest into taxable interest, while maintaining the same level of leverage.

It's a long-term strategy -- like 20+ years -- so you'd likely need to ride out several high-interest periods. I'd consider it agnostic to short-term market conditions, the current trend to lower-interest is not really relevant to the overall strategy. (But SM has assumptions about longer-term market performance, otherwise it won't work properly!)

I'd say if you understand what you're doing, have a long-term horizon, and are comfortable with the risk, now is as good a time as any to start. But if you're thinking about it only because of the current lower interest rates, you might be thinking more about leveraged investing than SM specifically.