Some consumers have complained that iPhone 12’s magnet is not strong enough to keep MagSafe accessories in place. Internal testing apparently shows that this won’t be an issue with the battery pack as its ‘magnetic attachment system has proved strong enough for the charging unit to stay in place’.
Currently, Apple seems to be experiencing some software-side issues and this may interfere with its original plan of launching the battery pack some months after the release of the iPhone 12. Apparently, iOS sometimes erroneously shows that the pack is overheating. There also seem to be issues related to switching between using the accessory on an iPhone with and without a case.
Apple has seemingly also talked about making other MagSafe accessories, including an in-car attachment.