pesticides must be applied more frequently to get the same level of protection. This is one thing which drives up cost. And of course every application carries the potential of exposure for farm workers.
I mentioned neem because I have worked in Africa and observed that much of the farm work, particularly pest management, is done by women. OTOH a big advantage of things like pyrethrin and neem is that the farmers can grow their own insecticides. Commercial pesticides are out of reach or unavailable for many farmers in places such as Mozambique.