Yes, you want to keep a viable population because they may be a gene modification delivery system. In warm countries, it is the cheapest and broadest way to "infect" a population. If you do find a way to do RNA insertions from injectables, this would be an ideal system.

Perhaps that is why we have them. My friends had a similar discussion on HIV a long time ago, that it may turn out to be the ultimate cellular insertion tool we ever come across. As i recall, if you have HIVb, you body doesn't develop AIDS, so a de-weaponized HIV virus may become a tool down the line. The same may be said about malaria and the other apicomplexans. They have little organs at the front of the parasite that allow them to easily slide into cells, videos make em look like they just swim up to a cell, and nose into it. Pretty amazing biology