It's important to have multiple sources of income, especially in a competitive field such as comic-making.
Personally for me, Ink supporte has shown more growth than ad revenue. But even then, the money I've made so far is good enough for a lunch or so. It's nice pocket change, but it won't make a sustainable income. I don't have an audience quite big enough for that, so I'm still promoting here and there and just engaging the community.
It's why I also have a Ko-fi and a Patreon, as well an upcoming internship to earn an income. In general, it gives me a better sense of security, knowing that I have money coming from different directions. While the money I make now is more suitable for a college student than someone living on their own, it's still gone to my savings here and there.
Every little bit helps!