A tool that handles a frequent but not particularly challenging problem is still a net win. Humans make errors. The more times I have to do something manually, the higher the likelihood I have screwed one of them up. I don't expect to get better at doing a task the 101st time. But I do expect the odds that one of them gets cocked up to climb ever so slightly. Better if the machine can just do it.

If the majority of the code is written by middle-of-the-road team members, then most of the merges will be done by those same people. Something that never helps me with my changes still helps me, due to my shared responsibility for the project. This is an often overlooked aspect of the tool selection process.