JollyRancher
Yeah, any cell provider is bad for privacy simply because of how the infrastructure works. No one can really change that. All we can do is compare incremental details.
However, this is not strictly true:
doesn't provide any data about your number/account outside a court order from a US court
Cape says they don't collect and sell any of your data. However they say they use third-party providers for a lot of their services, and they do specifically mention that the third-party providers have their own independent privacy policies.
Effectively, Cape just seems to be branding for a very thin wrapper around existing third parties (just like all regional carriers), and while Cape themselves don't actively try to collect your data (and charge a premium for that fact), the third parties absolutely do collect your data no differently than when used by any/all other carriers.
This is still a very small positive privacy increase relative to the other major national carriers that try to collect your data (even from their equivalent of that thin wrapper of what Cape actually provides directly), I don't dispute that, but that's the same thin wrapper that virtually every Regional carrier has/uses. And most regional carriers don't have the resources or market for capturing your data, and are significantly cheaper as well.
I'm assuming it's practical experience you're citing for this statement:
Cape let's you purchase and pay anonymously (prepaid Visa bought with cash will work
Which is surprising since Cape says they just use Stripe. The same thing almost every online marketplace uses for all payments, and notorious for mandatory KYC. Maybe there's some loophole in the restrictions here when used with a prepaid credit card though, given that Cape offers prepaid services rather than post-paid. Either way, good to know.
Notably, Cape does not have equivalent pricing to national carriers perse. While the national coverage and data are equivalent, every national carrier has other side benefits that are included in their prices as well. One example is international coverage, which Cape specifically says they do not support at all on iOS, and only have limited support for on Android (currently). All national carriers have coverage in almost every country, though you may not get data or have very slow data, and may have to pay a premium by minute for voice calls. I'm not necessarily saying the side benefits from national carriers are very good, it depends on your individual needs and use cases, but they do exist and have to be included in the comparison for a real apples-to-apples price comparison.
And relevantly, they have better national coverage than any regional carrier that they're most similar to (though equivalent international coverage), so there's that fact as well when comparing prices with regional carriers.
Practically, it seems like Cape trades the miscellaneous national carrier side benefits for a thin layer of some privacy. If that's the side benefit you prefer for your use cases, then it certainly seems like a decent choice (for now, until they get purchased by someone and all commitments potentially go out the window). But it's nowhere near what the marketing tries to suggest is all I'm trying to flag.