anahata, exactly,if someone wants to have their 20 key box tuned in meantone,ok, but dont expect to be welcomed by other free reed players,who are tuned in equal temperament.,
neither will they fit with fretted instruments such as guitars,who are also in equal temperament,particularly if the player is using standard tuning.
why should a guitarist ,have to accomodate ,a mean tone instrument by leaving all the thirds of a chord out.
meantone boxes are ideal for solitary players who like to play on their own.