I have seen that certain people said that market will never sleep. As I know, like usual market at NASDAQ or NYE Stock Market they usually open their market at 9.30 a.m. to 4 p.m. So why does it call market never sleep? I am curious. I am new to this kind of thing
The markets you described above are centralised stock markets.
They do have fixed time and weekends for their time of operation. Those markets are different from the crypto markets. Crypto markets are fully decentralised which does not make them go offline anytime due to the global markets. Peoples globally trade on the markets to buy or sell their cryptos which keeps the markets alive for 24/7 and on any day.
These are two different markets and i would suggest you to first go the the defination of crypto markets to get what it actually is. Stock markets are completely different from the markets here. You can check various exchanges for cryptos working always without any such gap.