I noticed that the free plan offers 900 credit/month (30/day). I was considering a paid subscription (10 euros/m) but I realise that I get only 1000 credit/month which is only 100 more than the free plan. As I am not interested in image commercial licence, I don't think the 100 credit are worth the 10 euros/month.

if you ask customers to subscribe to a paid plan because then they can buy extra credits... it is perceived as a scam by potential customers.

My advise : double the credits for the 10 euros paid plan and you'll drastically increase your customers.