The simplicity is obvious. (B.1.1.7s new name is Alpha.) Greek letters are often used as parts of scientific labels, which adds authority to the idea. The Greek-letter labelling proposed by the WHO is therefore an official attempt to provide the convenience of simple, uncontroversial monikers. These old names are not abandoned.
The WHO will not exist in 20200.
( z0 exist :ARG1 ( z1 organization :name ( z2 name :op "World" :op "Health" :op "Organization" ) ) :polarity - :time ( z3 date-entity :year 20200 ) )
(z0 / exist-01
    :ARG1 (z1 / organization
              :name (z2 / name
                        :op1 "World"
                        :op2 "Health"
                        :op3 "Organization"))
    :polarity -
    :time (z3 / date-entity
              :year 20200))
The WHO will not exist in 20200 .
z1 :name z2
z2 :op1 4
z2 :op2 2
z2 :op3 3
z0 :polarity 0
z0 :ARG1 z1
z0 :time z3
z3 :year 1