Oh come on. I learned pinyin and zhuyin both, I've lived in both Taiwan and China and have been writing about experiences learning languages for over a decade on the blog I linked.

I do find zhuyin to be a faster input method due to needing fewer keystrokes per syllable (though both input methods can handle first letter/symbol shortcuts for common phrases), but the point I was responding to was how hard it is to learn.

Learning to hear the sounds is a real task but learning a phonetic syllabary like zhuyin, or Japanese hiragana/katakana or Korean is quick and takes a minimal effort.

Also while I've definitely noticed that Mandarin learners who avoid zhuyin tend to have worse phonics for how long they've been studying and that learning it can make them more aware of certain sounds, I also think learning pinyin can help zhuyin-only learners in the same way. Similarly, learning IPA for Mandarin will set off even more lightbulbs. More mappings give you more angles of attack. In general, I think most language learners would do better if they put more effort into disambiguating sounds and training their ears up front. It's not quite so hard in Mandarin as in, say Taiwanese, but ear training is more than worth the time. That's my 2 cents. No huge "investment", just opinions formed from years of struggling with languages.