You mean as experience in buying? Sure, why not? If you find something at a price you like, buy it now speeds everything up. You buy, you pay, you get your item.
Whichever way you want to buy, do take the time to check a seller's feedback comments. Buying something breakable? Does the seller have feedback praising packaging? And so on.
If you mean as a seller, the buy it now option is not available to you until you have some experience unless you open a store, which I would NOT recommend until you have some experience.
Radine