My golden rule is: if I didn’t give you my email address and you’re sending bulk commercial email to me, you are a spammer, you immediately get reported as spam, and you get put on my shitlist so even if you reach me some other way, like from an advert or connection, I won’t buy from you.
If you are sending commercial email to me, the absolute bare minimum I need from you to distinguish you from a spammer is to know how you got my email address. This is something that the spammers never provide.
Services like this all seem to be aimed at black hat spammers who buy emails without consent and who I definitely don’t ever want to email me. Note how there are features intended to evade spam filters listed, but absolutely nothing about consent, opt-in, things like that.
The links in the footer: Privacy Policy – dead link; GDPR – dead link; Cookie Policy – dead link.
The reason why these services need to spend so much time talking about deliverability is because people report them as spam, which rightfully harms their deliverability.