Absolutely identical projects will not be exactly, because everyone will try to differ with the help of additional functions or conditions, commissions, speed ...
Of course, there can not be absolutely similar projects, since projects are created by different people. But you need to understand that the separate functionality of different projects may coincide. But the first project that will provide a working service will get the majority of users. Remember ethereum and many other platforms with smart contracts?
The coincidence of some moments of functionality on different platforms does not harm anyone. Because the success of the project depends on a large number of different factors.