Lots of the above facts are correct but some not strictly true allow me to ellaborate a little.
Bitcoin is not strictly anonymous it can be traced through the blockchain to the original sender allthough impossible for you or I it can be done by a specialist, there exists tumblers that send the coin to many different addresses making it extremely difficult probably impossible to trace but you must know that you can trust these companies that do it.
It is irreversible in that it cant be charged back like PP So traders choose to use it because there exists shady buyers also who try to "claim they did not receive the goods"
You can compare it to £ or $ or any other fiat currency but remember it is volatile in that the value can drop or increase perhaps thats what makes it exciting amongst other things for buyers and sellers alike you can learn more about bitcoin and other cryptos at the link below.
Thank You Reading