Felt kinda same same upset, 'cause double-CHAD is long challenge , but baby isn't really worth the efforts.
Instead of waiting same time and getting 2 hearts, i'd much more prefer getting one heart 2*faster.(especially as at high stages there are only 6 heart slots available, and waiting long/getting lots of hearts at once isn't a desired behaviour).
'Cause(if you don't know) in late stages there is a limit to only 6 hearts store, so WHY player would want to use slow speed double-hearting baby, that constantly overflows the limit?!(plus cost more and recharges longer than single one, so much more difficult to fill loses after big waves)
Twin-CHADs "seems cool" only on first stages, when there is no heart limit and OP enemies.