Apart from the fact that there are more demand of cryptocurrency in Asia (most especially Bitcoin) than any other part of the world which obviously will lead to the price of coins in that area been more costly to afford than countries with less demand of bitcoin. Like there was when countries like venezuela and Zimbabwe which aren't located in Asia has also recorded a high spike in the prices of bitcoin in their respective regions, the price is just determined by the demand naturally excluding the fact that manipulation are carried out by the exchange providers as some point to favor themselves.

On the other hand, countries not using USD as their fiat currency has a disadvantage as the exchange rate for their local currency could affect what the price of bitcoin is trading at in a particularly exchange in the country. Example, the official exchange rate of Naira (Nigerian's local currency) per dollars is N382 but that's not the case on exchanges like Luno or even Binance. Luno is trading Bitcoin at N455 per dollars while Binance is trading at N472 (the last time I check which is just approximately 2 days back).

Now using the official exchange rate to calculate what the price of bitcoin should be and that of the exchange rate for each exchange, you'll find out it'll be more costly buying in those platforms. That's
Luno trades at N4,929,999
Binance trades at N4,946,501 meanwhile (using official exchange rate), the price of bitcoin should be N3,999,158. Calculate was done when bitcoin was trading at $10,469