So let me get this straight, this i like Paid To Read but instead of giving 1 cent (for example) to read an e-mail you just give them token?
Not a bad idea to be honest, but have you ever though this may get abused rape? I mean same person with multiple e-mails bot?
They have addressed click fraud and abuse prevention in page 15 of the whitepaper. Sendy will employ variety of abuse prevention strategies including machine learning, sender conversion verification and subscriber score compensation model.
what Sendy better than Gmail , yahoo or another provider email for free is good ?
I'am read whitepaper sendy . but , I'am not full understand about this project email.
I think you should read page 6 and 7 of the whitepaper again.

Once you subscribed to an email subscription of a company, do you get paid for opening those emails sent by the company at gmail, yahoo or live.com? NO
Most of the times it will go unread as you are not incentivized to open those emails.
There are over 59% of emails treated as spam and never read by the receivers which leads to a poor engagement. Hence it is a waste of money and time to most of email senders.
By incentivizing subscribers to open and click emails by giving their attention a value and rewarding them with SNDY tokens will increase the engagement rate which is plus for the email sender.
This means both parties are in a win-win situation.