Power
In terms of worldly power, you're pretty low on the totem pole. First, the point of being a nun or a monk is really about serving other people (not to mention the big kahuna upstairs). From soup kitchens to clothing drives to church-sponsored Toys for Tots collections, you'll spend your days bringing hope to the hopeless.
Poverty vows are a little more serious than campaign promises (source).
There's power in that, but it's not the kind that'll get people to make you President. Nor would you want it to; your profession is all about humility, chastity, serenity, and grace—not exactly ideals that work well with a ruthless climb to the top.
Second, there's a long line of religious bureaucrats between you and God. It starts with your abbot or bishop, whose dictates you need to follow. These people and the longstanding monastic tradition that predates them will regulate your days.
That includes what time you eat and when you sleep. It's like a really gentle boot camp—one where you'll probably never have to do a push-up.
Though you have almost no power, you do get a few consolation prizes. You command respect wherever you go. You have all the "me time" you could possibly want. And let's not forget all that time you could spend learning Latin. It may be a dead language, but if it ever gets resurrected, you'll be the most popular person in town.