According to the update, Apple says, “Addresses an issue that could cause the battery to drain more quickly.” They also note, “Resolves an issue that prevented some users from accessing the ECG app in regions where it is available.” So if you are experiencing these issues, then hopefully the latest update will fix it.
That being said, we have heard reports from last month in which Apple Watch Series 3 users were experiencing crashes and random reboots on their smartwatch after updating to watchOS 7. This update to watchOS 7.0.2 does not make any mention of addressing those issues, so we’re not sure if Apple has another update planned that could fix it.
However, Apple has released a beta version of watchOS 7.1 that hopefully addresses those crashing and rebooting problems on the Series 3, so maybe Series 3 owners will have to wait until then for that update to potentially solve their problems.