Yesterday Tom has confirmed that C3 is not dependent on Chrome for offline work. So even if a new update from Chrome breaks C3 for online use , you can still use it offline via desktop app. I posted this since I see a lot of confusion about this subject in various topics.
Tom is also considering changing the payment plan. So maybe things will be looking good now.
The Good News
1) C3 is NOT Chrome dependent !!
2) Once project is saved offline you can open C3 projects and edit them on mobile.
3) Tom is considering changing the pricing model.