How do you know who to trust? You surely have to trust someone. It feels generally true that we can trust Apple since we pay them for hardware and their ongoing business interest is in protecting their revenue streams through their hardware and iOS app store, which means you are aligned.
Generally for Helm that's a good case. That's why we charge money for this hardware and software: it aligns interest.
Free cloud services are not truly free and that's what most people seem to be OK with... but not all people.
This is the classic trade-off. Open source software you can read the code but usability suffers. For the people on HN, most people can run their own servers, but for normal people that's not an option.
Apple has managed to create a computing environment that is highly usable for normal people. This is what Helm is trying to do too.