Why isn't there a Lotto app for Google Play in the UK?

[AC Question]

Why no lotto uk app for google play

I can see that The National Lottery have released an official lottery app for the UK, but why is the app not on Google play. I read somewhere is was because Google see this as gambling. That does not make sense as there are many Gambling apps on Google Play.

I don't want to enable Unknown Sources on my phone. Come on both Lottery and Google release the app on Google Play