As long as you can wait long enough it should always go up, because there's 3 built in methods of deflation. Which also means you should never sell bitcoin.

If you're interested in a long-term hedge, and all the 30% down-days are eventually offset by a soild long-term up-trend: yes, sure, why not?

If asset A reliably loses 4% of its value per year, in a totally-predictable straight-line, and asset B has wild up- and down-swings, but over years reliably delivers 25% appreciation per year - asset B is better, unless you'll be forced to urgently sell at unpredictable times. (And if you can find a basket of uncorrelated B-like assets, all the better!)

That’s incorrect. If I’m remembering correctly Nigeria was the second largest Bitcoin market pretty recently.

It is not that easy to do even in many countries with a developed banking sector. Bitcoin is very impractical as a currency.