In my opinion the memorization (with whatever method) gets you started. There is no good replacement, and in that phase any other learning activities really aren't as important.
Only when memorization has laid the basic foundation does it make sense to spend more time to read and write in the new language. In my opinion reading is the most efficient activity at higher levels.
I disagree. Even at the early stages you should be reading simple sentences with words you just learned and you should be creating sentences with structures you just learned.
I didn't say you shouldn't read simple sentences or do other activities. Variety is useful.
I said early on the most efficient use of your time is memorization of words and maybe grammar. Duolingo does that well, in my opinion. It doesn't do the usual flashcard stuff, but it does favor repetition and you can practice speaking and listening from the first time.
Only when memorization has laid the basic foundation does it make sense to spend more time to read and write in the new language. In my opinion reading is the most efficient activity at higher levels.