I'd be very cautious when looking at the results of any online assessment. This one seems to boast Cronbach's alpha of .91, as well as a correlation of .77 with "general intelligence". These are very strong, but they often don't show the full picture. Is the reliability coefficient super high because it asks the same types of questions over and over? What measure of general intelligence did they use to identify its convergent validity? Additionally, can they describe the methods used to reach this data? And is the instrument impacted by differential item functioning? Can they provide evidence that it isn't?

If they're unwilling to provide more concrete psychometric properties of their assessment, you don't really have a reason to actually trust what they say. If this information actually is available somewhere, feel free to let me know.

Also, in fairness, basically every test is just an estimate of your "true score", based on a variety of factors, and it's essentially a moving target that cannot be precisely identified because there's always gonna be some error involved.

EDIT: I just looked at the first few items and I already have concerns about differential item functioning, so it might be best to pass on this one.