Certain class upgrades are locked behind "Lucky Coins" which spin a slot machine. It is entirely possible to play for 100 hours and never get the specific scroll you need. An editor bypasses the casino.
: Be extremely cautious when downloading ".exe" or ".apk" files claiming to be save editors from untrusted sources. Many of these are "generators" that do nothing but install adware. The State of the Game Today angry birds epic save editor