In general CASE WHEN X THEN true ELSE false END could just be reduced to X. For example, a query seen in the wild contained:
((CASE WHEN (( generic.__time ) >= (TIME_PARSE('2018-03-08 00:00:00.000', 'yyyy-MM-dd HH:mm:ss.SSS')) AND ( generic.__time ) < (TIME_PARSE('2018-03-09 00:00:00.000', 'yyyy-MM-dd HH:mm:ss.SSS'))) THEN true ELSE false END))
In general
CASE WHEN X THEN true ELSE false ENDcould just be reduced toX. For example, a query seen in the wild contained: