I can easily go to someone's place, make sure he votes for my candidate and give him 10$. A lot of people with low interest in politics would sell their vote, I suppose.
Polling booths are still safer than all other options (mail voting, electronic voting, etc...)
2. the vote seller can be paid only after the end of the elections, given s/he didn't voted on paper (it it all possible to authenticate wuthout eID on the voting station).
Is it always like this? I could also go at someone's place one minute before the voting closes.
Voting at the voting booth is still more secure.
I live in a country with only voting at the voting booth and I am perfectly happy with it!
In addition to this, the fact that you are not aware of voting fraud does not mean it does not happen. That's why it's important to care about potential voting fraud.
There was a proposal to install cameras on the voting booths, but it was rejected by the high court.
Surprisingly e-voting can solve these low-tech corruption problems, but it introduces a much larger attack surface.