Writing another "hello world" or "todo" application is boring. Gradually progress not losing the fun of coding. See improvements in my coding skills. Solid statement on my resume for the first job. Whatever is your reason you fond a good place to start. Sandbox ➔ Career ➔ Tournaments ➔ ML/AI
For software engineers
Sometimes work projects are not fun. Deadlines are too short for trying various algorithms. Not enough test data to compare strategies. With compute becoming cheaper, clients less care about benchmarking of code. Once for all demonstrate to your coworkers that your code is better regardless of coding language. Compare your skills across the world. Whatever is your reason you found a good place to poke around.
For IT companies
Hackathons are good, need another one. The company needs a reliable skills assessment tool. It's biases and time-consuming to judge potential employees based on a "take-home coding test". Bind the team in a competitive environment in a fun and company beneficial way. Whatever is your reason we can facilitate with automated tools.