This is a common "scam", there's an equivalent for many countries. I say "scam" because the service these companies claim to provide is an easier, guided process to apply for things than the official process. And, sometimes, for some people, maybe that's true.

If you're an EU citizen travelling to the US, that's kinda playing on easy mode, and the value add here is clearly so low that the $70 feels like a scam. If you're a citizen of another country with more complex application procedures, it could be trickier (although unlikely to warrant $70). If you're a less technically literate user and they have an easier to understand process, maybe it's worth it? I don't want to make that judgement call.

It is highly unlikely that your passport details are going to be sold on. It's somewhat likely that your email address will be sold on to advertisers. It's fairly likely that you'll get upselling emails for other services they provide, although you should be able to GDPR them. The aim is the $70, not to steal your identity. The business model is to be technically-not-a-scam, legal, and therefore not something that advertisers realistically can de-list. It sucks, but thankfully you're only out $70, and you'll probably be able to expense it, just don't give your work too many details about what it is.