I am interested, the single payment is a big plus.
Then however, the only sign-in option being google is somewhat of a turn-off for me. For a paid service, I would want to login with my own email. I am clicking away.
Back on the homepage I ask myself: Why is there no picture/pdf of an actual invoice? I only see some part of the UI.
1: I understand your concern in terms of google auth. I always refused to implement it because i did not want google to have information about my users, but every developer told me i was missing out on so many signups, so i tried it this time. Now it hurts me to see that a potential customer walked away.
2: In terms of the actual invoice, I will implement this instantly.
I hope it will be good enough one day for you to give it a chance. I appreciate you a LOT.
I think the key here is having it optional. I am personally far more likely to sign up to something if there's google auth - I don't need another thing to track I can just easily assign it to my work or personal account.