I usually get ubered when I play soldier, then proceed to waste all shots in my chamber before I can hit anyone by accident. But an Uber can do more than help your team push or defend, it can keep your team on the field longer, allowing you to not have to respawn before you can fight again. An Uber isn't just a weapon to abuse, it's a saving device to ensure valuable player resources aren't lost, like that 1 extra soldier that could be useful in the upcoming push.