Nope, your users need not have the toolset, that's the beauty of it! It creates binaries compatible with any distribution newer than the machine where you are compiling. E.g., if building on CentOS 6.7, anyone on 6.7+ can run your binaries.

We also have an application stuck on RHEL 6 because of end-users, and I'm happily using devtoolset-7 which gives me GCC 7.x, and quite a bit of C++17 support :)

Edit: My understanding is that it achieves that by statically linking in the "newer" parts of libstdc++.