1) When the BOINC servers come under DoS attack while gridcoin nodes are downloading the rankings, some nodes will have the rankings data, some will fail to get it. This would fork the gridcoin chain because some nodes will take into account the PoR bonuses (and all transactions using these coins), while others will reject them because they were unable to confirm the BOINC rankings. This fork would in effect break the gridcoin network until the BOINC servers come back online.

2) You can be as honest as possible, but many people still won't trust you. This is precisely why, eg., Stellar is not trusted and not embraced more widely, despite being set up as a non-profit foundation, with a charter, a voting system, being completely transparent, etc. People and companies around the world (especially those with a tendency to have anti-USA views) may not trust BOINC (hence gridcoin) because BOINC is operated in and funded by the USA. Do you think most, say, Chinese companies would be willing to fully embrace gridcoin, knowing it relies heavily on a US-based project like BOINC? No!

I can see your viewpoint though. People who care about science and who may already be BOINC users would probably like gridcoin. But most people in the world (unfortunately) don't care that much about BOINC, and when given the choice of Bitcoin or Gridcoin, they would probably go with the former (if only because of their anti-USA views, or because Bitcoin is already more widely accepted).