Africa (the unbanked) is where we really need to push adoption. I guess the issue is not having the internet (wifi or 4G). Imagine if even 1 in 1000 people had a mobile phone & a BTC wallet or something.
There is mobile internet - at least in cities and around highways. I think africa will be very soon show what's possible with bitcoin in areas with corrupt governments and inflated money. If smartphones become cheaper bitcoin could have a huge impact on the economy and society there.
And of course if LN works and transaction costs go really down. High transaction costs might be the main reason it is only used in totally wrecked economies (Zimbabwe) or "rich" african countries (Kenya, SA, Ghana)
M-Pesa is successful in parts of Africa - it's only a small step from there to cryptocurrencies.