Although the first Blockchain (BC) was proposed about a decade ago, BC achievements from a technical and functional perspective are measurable, but still face open issues. Since IFIP’s Working Group 6.6 on the “Management of Networks and Distributed System” investigated BCs in various aspects, this contribution here summarizes and clarifies key characteristics of BCs and their related approach of Distributed Ledgers (DL).While many properties are under discussion, the two approaches differ measurably. In turn, the value of BCs and DLs is outlined in combination with selected and exemplified application domains. However, a set of open issues has been observed, which possibly hinders a practical operation, e.g., due to excessive expectations, missing interoperability, wrong scalability promises, or out-of-scope trust assumptions. Thus, the state-of-the-art in BCs and DLs is clarified and current as well necessary research steps to follow complement this state.