C3 is too expensive if you are not professional game developer. And free version is too limited for anything useful.
Typical usage for me is to make games for private use, like a greeting card for kids birthday, fool around with some game mechanic, or recently when I made a game for World Cup final (that became surprisingly popular). I did publish few game made with C2 on Google Play Store but nothing very successful or even polished enough to make impact, after all I am not full time game developer and don't kid myself that I am very lucky.
Maybe one of those game I publish will be profitable some day, but until then it is too expensive to give so much money regularly.
It's not just C3, but any "cloud" software these days, my opinion is that if you want receive money from me regularly then prove to me that you worth it for my perceived usage and that I will use it regularly. Right now C3 have two modes of usage, pro or free, neither looks suitable to me. If this pricing plan was active from my first use, I would have paid 600$ up until now for few games that don't return any money.
Second problem with assurance to pay aka Cloud approach is being locked out of your own work. Recently my niece wanted to see how I made one game birthday greeting card from 5 years ago, and then wanted to change a picture to a new one. If I had C3, and didn't pay, it wouldn't be possible, and I don't want to be locked out of my memories.
I understand how expensive development is (being developer for 20+ years) and Construct developers made a great product that deserve to be praised (and paid) but rental approach of C3 is forcing me to calculate how profitable acquiring C3 license is, meaning, I won't pay C3 until I know I have return of investment through some product made in it.
That said, C3 is the future and (will) have better features, C2 will slowly fade out, but nevertheless I agree with Jayjay and would advise to start with C2.