There is nothing which Apple Intelligence can do that a hypothetically evil Apple couldn't have done before, given sufficiently treacherous code in their operating systems. Thus if you use an Apple device, you're already trusting Apple to not betray you. These new features don't increase the number of entities one must place their trust in.

Whereas with apps like Gmail and WhatsApp on an iPhone, you must trust Google and Meta in addition to Apple, not in place of Apple. It doesn't distribute who you trust, it multiplies it.