You can burn plastics into energy or reuse it. Temperature should be high enough to avoid toxic byproducts.
Consider:
hydrocarbons -> energy
vs.
hydrocarbons -> plastic product -> possible recycling -> energy.
Plastics can also be made from cellulose. If this route is taken and becomes more popular, you could grow stuff, make it into plastics, use it, then bury it to store rid of carbon. Possibly turn plastics it into cubes and drop them into some deep place in ocean without volcanic activity where it stays inert hundreds of millions of years.
Sure, you can burn plastics -- but releasing even more CO2 is not attractive. There is a lot of talk about ways to sequester carbon -- it seems like throwing away tons of plastic is doing exactly that. Now, I'm sure it could be done in a better way that is currently being done, but burning it seems like non-starter.
Consider:
hydrocarbons -> energy
vs.
hydrocarbons -> plastic product -> possible recycling -> energy.
Plastics can also be made from cellulose. If this route is taken and becomes more popular, you could grow stuff, make it into plastics, use it, then bury it to store rid of carbon. Possibly turn plastics it into cubes and drop them into some deep place in ocean without volcanic activity where it stays inert hundreds of millions of years.