Just reading the wikipedia article on GISAID is enough to start the alarm bells ringing that this is not all it is supposed to be. Here is the Max-Planck statement on funding.
Why I dislike it is that for a database that is supposedly open and for sharing it is surprisingly difficult to actually gain access to it. It has password access and you have to apply for an account. The researchers who publish data there don't do so to enable the world to access it - send it to the EBI or NCBI to do that. They deposit there to actually restrict access and attention. It is in a different structure to the NCBI database with different segments, it is harder to search and produces harder to download search results. It is a nightmare with little reason to exist.
Regarding its initial supposed reasoning to prevent unscrupulous big pharma from exploiting influenza vaccine markets it is interesting that it was inspired not by scientists but by a business investor. Like the SNP database this is a way of spiking intellectual property of competitors by making it public domain and so no longer an interesting discovery.
This is an interesting news story from last year about an accusation of an academic collaborating with big pharma to smuggle influenza virus and about corruption.
Here is that same researcher talking about GISAID when it first had legal issues in 2006 (at that time I didn't care less about influenza or virus work).
That same researcher was also caught out in a review article where her co-author had self plagiarised, a paper written about the same time as the 2006 GISAID relaunch.