As far as I understand the test cases of a codeforces competition aim to make all solutions with a certain complexity get accepted, all the slower ones get denied. The fact that no one cares about the "constant" of your solution if the complexity is right is surely cool because it makes participants think more about problems and less about implementations, but it also has it's drawbacks, the major one being the fact that in real-world scenarios those constants are often what actually makes the difference. Keeping the codeforces competitions that we all know and love unchanged, wouldn't it be cool if there was another kind of competition, maybe with slightly easier problems, where the participant's goal is to provide the best possible implementation? Maybe not even a full on competition, but just a repository of world-record class solutions to problems would be nice. I find it's sometimes fun to try to optimize something to death.