If you have never heard of Revolut, you are missing out on something revolutionary, big time!
Especially in a country like Tanzania, where access to a credit card is so difficult, a prepaid MasterCard can solve you a huge problem if you want to pay online on website that only accept credit cards or debit cards.
Also, exchanging different currencies quickly, at an inter-bank rate, within the same account, in real-time(!), with a few taps on your phone, is something that very few payment providers offer yet.
So go ahead, give it a try!