Sigh… While incubators do provide you with DNA, you cannot control the type of DNA that you receive from them. Frequently, for the 3-hr and 15-min incubators, the DNA is strictly for Commons and Rares–often for creatures that don’t have hybrids. Furthermore, unless you’re buying a ton of incubators, you’ll have a hard time getting the DNA you need for the creatures and hybrid components you need to do well in the “late-game” arena. It would probably take you ages to unlock T-Rex with this method, and probably several months to level V-Raptor and T-Rex up to level 15 to start trying fuse for Indominus Rex. Not to mention the fact that you can only hold a limited number of incubators, and speeding them up is an expensive waste of in-game bucks.
Instead of arguing for removing the Battle Arena entirely, which won’t be happening, I recommend putting in the time to dart dinosaurs “in the wild” around your neighborhood or local park. It’s a much more effective strategy for strengthening your team, and you’ll be able to better focus on bolstering the more important members of your collection and team. It’s the whole purpose of the game, really…Best of luck!