As the person who made this call originally at Facebook for the apps--it's not worth it. Any sufficiently advanced or motivated person/group/government would break through eventually...such is the nature of shipping client binaries. You can spend a ton of time and money trying to prevent it (for example Pinterest once was trying to ship their own custom language + vm, which I advised against) OR...just accept that your client code is compromised by default, put logic on the server, and move on with your life.

Cert pinning is basically free and is sort of a "you must be this tall to ride the ride" thing--not secure, but keeps the riff raff out.