Like most Drosera, you can leave the flowers on Drosera binata without much if any set back. In my experience the T form of binata does not self pollenate (neither on it's own or with your help). Drosera binata propagate so readily by root and leaf cuttings that you're not missing out on anything by not being able to collect seed.

A quick clarification about VFT flowering. While flowering does slow down vegetative growth in flytraps, they are quite unlikely to die from flowering. If a VFT is not longed for this world, flowering can tip it over the edge but that's more of an reflection of the health of the plant rather than the detrimental effect of flowering. If your plant is healthy and you want seed don't be afraid of letting it flower. Of course we grow VFT's for their traps not their flowers so, if you don't want seed, cut the flowers off and let the plant redirect its energy into more vegetative growth.