If you perform all the games in the way you want. Absolutely not. You're effectively pumping more power into a component to increase its performance. If you're performance is adequate, why add more? In addition to this, you're also adding more stress onto the component. And poorly controlled overclocking ultimately reduces the lifespan of your components.
It's like boosting a gaming PC 16GB of RAM to 32GB because more is always better right? No. Most games nowadays don't even touch 16GB so effectively you're just caching another 16GB+ of RAM.
So if you WANT more performance, go for it (but please do read up on it as so many people can do it badly). But if you're happy with the way it currently performs. No. But GPU overclocking is typically a lot safer than CPU overclocking. And in some games, you may see a 5-10fps increase by overclocking a 1070 ROG. But it also depends on the rest of your rig.