Does the game want to advantage people who can log in more often?
There should certainly be some, albeit slight, advantage to logging in more often. Even if it's for getting the best deals on the transfer market or tweaking your training minutes, or for some other system that someone is bound to come up with. More active players should have a slight bonus over less active managers.
Buzzerbeater is not a real time game, where you really have to log on every 2 hours to achieve anything - unlike some other popular internet games. True, there is a certain amount of micromanagement built into optimizing your team training, but on the other hand, missing a lineup once in a while isn't going to be that detrimental to your chances of success. It's not as if time spent logged on to the game is a huge advantage.
Sure, we could reduce the training challenge to make it easier. But, somewhere down the line, someone is going to suggest a bid agent for the transfer list so you don't have to be online for player deadlines and then someone will suggest an automatic transfer list scan for when you're looking for a player and don't have the time to do it yourself. Both of which aren't really challenges either - you just have to log in more often to be more successful at doing them.
We could implement all of these automatic processes in the game - it's more than possible to build tools to do it. But I seriously doubt that many people would actually log in, click a few buttons once a week and enjoy the game.