As for whether it's appropriate to wear, who cares? They're comfortable, they do everything pants can do, and did we mention that they're comfortable?
Okay, stop right there — I am going to end the "are leggings pants?" debate I mentioned before once and for all. It seems that some people are confused as to how pants work, considering they're just a garment that both legs are put into. They aren't defined by the type of fabric they're made out of nor what shape they're cut into. According to Merriam-Webster, pants are defined as "an outer garment covering each leg separately and usually extending from the waist to the ankle." Hmm, it seems that according to this definition, leggings most certainly qualify as pants!
I don't really want to have my outfit choices philosophized unto by you or anyone else, so unless I ask you your opinion on my leggings, please keep your thoughts to yourself. I think people who ask this sort of question are just jealous of how comfortable we legging-wearers are and just want to feel better about their stiff pants-wearing habits. After all, isn't insecurity the first culprit of criticism?
Ruthie Friedlander at Elle takes the opposite stance, saying leggings are the easy way out. There's a difference between loungewear and the clothes you wear to be respectable. Loungewear is for lounging around, athletic wear is for working out, and real pants are for life. It's about wearing the appropriate clothes for the occasion, not matter how big or small it is. You wouldn't wear something formal to the gym, so why would you wear gym clothes to work?
Karl Lagerfeld once reportedly opined "Sweatpants are a sign of defeat. You lost control of your life so you bought some sweatpants." I do tend to agree—there's a sense of defeat and of not-caring that clings to this type of clothing. When I see people leave their houses in the morning to grab a cup of coffee still in last night's sweats, I wonder why they simply couldn't throw on a boyfriend jean and a sweater.
Why not opt for a black jean if you're going for a fitted pant look? Or a baggy boyfriend cut, if a cozy cut is what you desire! There are plenty of options that keep you looking chic and buttoned up.