“Check-circle” is exactly the amount of information that the able reader has. Sight-deficient users are as much used to those weird words as able users are used to unintelligible icons.
In other words, eyes can skip over decorations without the developer needing to flag them as such, but audio can't auto-skip.
It would be trivially easy to use ARIA attributes to indicate which span is the icon's label. Not something most people consider, but this is Google. At least they have an accessibility icon?
By the way, your comment shows an ableist bias: an analogous assumption would be that a person who cannot walk is content because they are used to a wheelchair.