How to explain Bitcoin to your grandparents

What is Bitcoin?

Bitcoin is a currency like $ ¥ € .but Bitcoin is a decentralised.digital money created,held and spent electronically in the world.

What is different between Bitcoin and money like € ¥ ₹ $

1-bitcoin governed by mathematics and distributed computing while money is governed by central bank

2-bitcoin international transfer within a few minutes while money transfer takes a several days

3-bitcoin backuped by product, service and a sound consensus of users while money backuped by product, service and economy of issuing country

4-bitcoin international transfer cost is 0 to$0.01 while money international transfer cost is 2-3% of transection