Hippocrates and Galen advanced the concept of humorism, a theory which held that we get sick from imbalances of the four basic substances within the human body, which they identified as blood, phlegm, black bile and yellow bile.
If I bought a pair of $190,000 Focal Grande Utopia EM and found out the beryllium isn't any more pure than a pair of $2700 speakers, I'd be very upset. I would also be upset if the beryllium tweeters in my $190K speakers cost less than diamond tweeters in a pair of $5K speakers.
Beryllium is used in alloys with copper or nickel to make gyroscopes, springs, electrical contacts, spot-welding electrodes and non-sparking tools. Mixing beryllium with these metals increases their electrical and thermal conductivity.