mullvad has one of the best reputations in the entire consumer vpn space. they were one of if not the very first businesses to accept bitcoin back in 2010 when no one knew what bitcoin was and before the word crytpo existed or anyone was in it to make money. they were one of the early funders and supporters of wireguard itself before it was merged into linux(and before anyone cared about it). they are working in cooperation with firefox to run their vpn system. they require no email address or personally identifiable information at all to use them. they don't do scammy sponsorships on podcasts or youtube channels to mislead people into thinking that their service or vpns in general solve problems they don't actually solve.
and at the end of the day if you think consumer vpns are stupid you can always just not use it. i don't think that them teaming up with mullvad implies anything bad or suspect about either of them. this type of a service is something that is really important and useful to a certain subset of users, and if they were going to wind up teaming up with a consumer vpn provider this is probably the least shady and most principled one they could have done it with.
and at the end of the day if you think consumer vpns are stupid you can always just not use it. i don't think that them teaming up with mullvad implies anything bad or suspect about either of them. this type of a service is something that is really important and useful to a certain subset of users, and if they were going to wind up teaming up with a consumer vpn provider this is probably the least shady and most principled one they could have done it with.