Bitcoin Core source code contains more 100K lines of code(80K of C++ only), Nxt is more than 45K line of Java code. All parts of the design(network/transactional/consensus protocols) are mixed in a hard way. So researchers and developers are not in good start positions to make experiments. In opposite, Scorex core is less than 4K lines of Scala code. Abstract core concepts allow to implement a broad range of systems, including ones with multiple types of blocks and non-linear history.