As Satoshi Created the Bitcoin and designed a protocol to be an inflationary currency as the value of bitcoin is volatile. Also as bitcoins inflation always decreases every four years because of this bitcoin halving. As of now, the BTCs inflation rate is around 3.6% and we are expecting it to drop to 1.8% after the bitcoin halving event. Comparing it to the average central banks, the cryptocurrency has a lower inflation rate.
When someone tries to buy all the worlds supply of a scarce asset, the more they buy the higher the price goes.
As the supply of bitcoin is limited, the rewards of the miners were decreased every 210,000 blocks.
The Central Banks telling the public the average inflation rate is at 2% but could indicate higher than up to 10%.


The estimated inflation rate increase in 2020 is at 2.5% because of the bitcoin halving.
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Reference:
https://news.bitcoin.com/bitcoin-halving-inflation-rate-central-banks/