There's no reason to believe that we've reached the optimum point for ending scientific research in any particular field. If we'd stopped medical research in 1900, the 1918 flu pandemic would have been worse. And basic research doesn't have a label telling us how it's going to be useful, yet the evidence is pretty strong that basic research is worth the money.
Regarding your specific example, isn't it worth knowing that the mutations to make that virus (1) already exist in nature, and (2) aren't really that far from being naturally incorporated into a single virus. If it took 500 passes instead of 10, we'd be relieved to learn that, right? In short, it seems like this kind of research is likely to be of practical use in treating serious flu virii (spelling?) in the relatively near future.
The question is not "Is it useful?" but "Is it useful enough to justify the risk?" In that case, the answer might well be yes, but there will probably be cases in the future where the knowledge is not worth the risk.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
(I plan to make these threads from now on. Downvote if you disapprove. If I miss one, feel free to do it yourself.)