Hero/team power is useful as a rough metric of how leveled a hero or team of heroes is. That is the full extent of its utility. However, because it is prominently displayed as an easy-to-read summarizing number, team power is also being misunderstood as “team effectiveness”, which it certainly is not. All you have to do is take a look at any of the innumerable raid complaint threads that start with “my 2700 power team can’t beat a 2400 power team” to see this misunderstanding in action.
To help alleviate this issue, I would suggest removing the team power metric entirely from the game. It provides no extra information that a cursory glance of the team couldn’t give, and it only seems to induce frustration for newer players, so why not just remove it?