Centralised crypto is a code-based resource built to be employed as a medium of trade. Additional units may be created by mining. Everyone can do this if they have a a computer. Mining uses a lot of time and electrical power, however. A powerful machine is also needed, to do this successfully. Conversely, XRP is a centralised asset, which can't be mined. A fixed amount of units were generated by the company and this number will not be added to.