I guess it boils down to what your goals are (similar to what many have stated above).
If you merely want to learn to play a song(s) you listed, certainly you can laboriously figure it out, one by one, but your skill as a pianist will be very limited, since you're not necessarily learning "how to play piano" and more so an immediate gratification mindset of getting a song done.
Those songs you listed are "easy" to me (I can play most of them instantly on any key by ear), but I've been figuring out piano chords/etc. for more than a decade. Even then, I wouldn't play it as technically well as most people in this forum, since my technique sucks but I have solid by-ear "theory."
If you want to eventually be able to impress the masses (not necessarily other musicians), then perhaps my route works for you (learn chords), since you'd be able to play the popular songs very easily. For example, couple weeks ago I was playing on someone's Yamaha U3, and asked them to literally play anything on YouTube, and I instantly played those songs (easy songs, such as pop/r&b/disney etc.) But you'll likely never sound good playing classical, more complex stuff.
If you want to be a "pianist" in the prevailing definition sense, or "true pianist" sense, then definitely take lessons with a great teacher, and learn the skill of patience.
My two keys, I mean my two cents!