Perhaps! I'm no means an expert but I personally think of Steem Power as an interest-accruing "savings account." The more you have in SP, the more you increase your reward power -- ie. the ability to give your own posts increased dollars, or to upvote other people's content with higher dollar amounts.
The drawback to SP is that it's less liquid...I think it takes some time to power down from SP to regular Steem. Thus, if Steem should ever go "parabolic," it's best to have more Steem coins to cash out before the incoming "bank run."