Does gitmore just call GitHub API or counts by commits manually?

No thanks.

Yes, many teams use Gitmore to eliminate or reduce daily standups. Instead of synchronous meetings where developers report what they worked on, Gitmore automatically extracts this information from Git activity.

If your standups are just reports of what code the dev worked on the previous day then that sounds like a great thing to automate away, and Gitmore is likely a great way to do that.

However, that also means your standups are a pointless waste of time, and the solution shouldn't be to automate the pointless waste of time, it should be to improve your standups so they're actually useful. Rather than just saying what code the devs wrote you could use the time to discuss problems that came up, where people are blocked or where they believe they might be blocked in the next couple of days, or just have a bit of a check-in with everyone to see if they're feeling good about their progress. Standups shouldn't be simple progress reports; they should be an opportunity for the team to come up for air and chat with one another. If you're missing that then you're not really a team, you're just a bunch of individual devs working in the same domain. That sucks. The solution isn't removing the meeting with automation.