This is an awesome addition that provides a whole new level of utility for the reports. This means that now we can use them to dissect different periods and in practice even moments of our steem activity. This will allow a much deeper insight into what's happening to our accounts or the accounts of others we might be looking at for some reason.

It doesn't sound like the biggest of changes, but I think it's an important one and it brings the tools to a whole new level of usability.