This growth is caused by an age-old thirst for profit by ordinary people. Having seen that the new currency has taken root and shows stable growth, people rushed to buy it, wanting to earn extra money. People are buying - demand is increasing - the price is growing - more people are buying, demand is even greater. And in this way, a kind of "bubble" is inflated.
The original purpose of any currency is to help people in trading transactions. Those. money must be bought goods and services. This is the basic demand for currency.