For those million timestamps I am sure that those extra allocations from the statement APIs are not helpful. Since he references the C code sqlite is using (at a quick glance it looks pretty contained) I don't know why he doesn't just include it directly in his project and call it from objc, no statement API needed.
[Edit: I see now that in the test there is only 1 statement object ever created for a test of a million dates. Better than I thought initially. But my guess is the statement object still creates some degree of inefficiency not found in directly calling the C version.]
7 seconds is a long time in CPU terms, I am sure that he can do better.