To defend this site, that is the claim of the vendor and I wouldn't expect a site that focuses on listing EU alternatives to be critically evaluating a claim like that which hasn't been explicitly nay-sayed by any regulatory agency. Plausible uses a visitor id based upon a hashed + salted user agent plus IP address where the salt is rotated daily. The choice of whether consent is required for that is for the individual implementing site to make up their mind upon, but I don't think the vendor claim is unreasonable.
A similar (but better, IMHO) site that focuses just on analytics is: https://newmetrics.io/
The cookie law™ clearly lays out that technically required cookies can be set without explicit consent. Performance measurements are not a requirement though.
So if you are not using anything but essential cookies on your site, you don't need a banner.
> Because it does not use cookies there is no need to show cookie banner for this service.
which is a blatant lie/misinformation. The ‘cookie law’ has nothing to do with the actual use of cookies.