First, asking questions you don't know the answer to is not a sign of being dim. It's the only possible sign of intelligence.

I haven't heard Dr. Cottrell speculate on the purpose of such research, and I haven't speculated either. To be blunt, I don't know why. It is obvious that such research could lead to biological weapons, however, and it is impossible to exclude that motivation. It is perhaps less obvious that vaccine development for potential novel zoonotic virii might be furthered by this research, but that is also a reason to do it. Research just to find out stuff we don't know is also done all the time, and could also be a specific impetus in this matter.

Regarding flu vaccines, I see your intelligence showing. While I have been researching the coronavirus outbreak, I came across information regarding influenza I did not expect at all. I don't have a link handy (I didn't save one because I didn't expect to face this issue) but I recall this: hundreds of thousands of samples from people that have been diagnosed with the flu have been taken and submitted to relevant authorities (presumably the CDC or similar). Of those samples 16% turned out to be the flu.

That means that 84% of diagnoses of influenza are not actually the flu at all. That also means that even if the vaccine on offer in a given year perfectly matches the outbreak of influenza that erupts, it will only potentially be of use in 16% of the cases diagnosed as the flu. This was both unexpected and startling to me, as I thought doctors had a far better track record of diagnosing the flu.

I should add that I only heard this in passing, and have not made any attempt to verify it at all. Given the provenance of this claim, I think you should definitely verify it before you make any health care decisions based on it. I do not seek vaccination for the flu, because I don't get the flu as a rule. I also was told by someone just this last week that their wife got the flu vaccine this year and immediately became ill with the flu, while they did not.

The fact is that most people do not understand that vaccination is not risk free, and that party reveals that risk is real and substantive. Certainly what is diagnosed as flu is blamed for causing ~400k deaths a year. However, if the diagnoses are only right a fraction of the time, most of those deaths aren't caused by the flu at all. It is likely that vaccinations also have a death rate, and since I don't get the flu, I'm better off not being vaccinated either, because I avoid that risk as well.

I do not recommend following my lead. I recommend doing careful and substantial research into everything I have discussed here, and more as well, and making up your mind based on what you find out.

Be well!