It seems it is able to generate wildly optimized binaries. So I wonder whether this is the reason it is not desirable here as it might optimize not so smart solutions so well that they squeeze into the time limit.
Interestingly timus supported Intel Compiler in the past.
Intel compilers generate more "optimized" code not because it's smarter but because it will use vector operations (SSE, AVX, etc.) where possible, while GCC is generating more platform independent code by default (ie. no vendor/CPU model specific instruction sets). In fact if you compile with GCC and enable SEE optimizations, 80% of the time it will generate faster binaries. So, to conclude: 1. You don't want faster code because of specific instruction sets, and 2. If you disable the specific optimizations on Intel compilers (I don't know if you actually can) you don't get any advantage.
Intel C++ compiler is proprietary software. Looks like there are free offers for e.g. students, but Codeforces does not seem to be eligible.