In the case of all the CW shows, for a while WB had a deal with Netflix to air the shows over there. The deal expires soon, if it hasn’t already. After that, no one’s sure where they’ll go. Having them here would definitely up subscriber numbers, but WB could easily decide it’s more viable on their personal streaming service instead.
Beware the Batman’s probably gonna be here soon, since it was about as popular as Green Lantern the Animated Series. Justice League Action I believe is still going strong on Cartoon Network, along with Teen Titans Go!, so they probably won’t be up here anytime soon.
And as for most animated films, a lot of them are licensed out to other services because WB makes money by having them there. So you might see various movies animated or otherwise leave for a period of time because WB decided to let Netflix or Hulu rent them for a bit, but they’ll always come back, don’t worry.