I don't have an authoritative answer or enough information to form a complete opinion, but getting BTU/h or kW (depending on if your country went to the Moon) out of the petroleum byproduct may be a better way to reuse than the green wash of the fantasy of recycled plastic.
The mining/drilling energy overhead is already embodied in the material, so it may be better not to waste that by burying it instead of getting some useful energy out.
The plastic container diverted for the bicycle pannier market isn't likely going to do anything to dent the flood of plastic waste.
This doesn't need to solve the issue of plastic to be a good way of diverting some away from landfill or reusing them. It's a type of reply/thinking I see on HN a lot, along the lines of "well this doesn't solve the entire issue", incremental progress and partial solutions are good, trying to come up with the uber solution to solve the entirety of the climate and waste issues just leads to analysis paralysis and solutions too large to effectively implement.
I didn't mean to dismiss the reuse aspect of the panniers, and I may have misunderstood the intent of "reduce, REUSE, recycle" higher comment but I interpreted it to be saying that burning the plastic wasn't a reuse.
My assertion is that burning it is also a form of reuse and possibly better than putting the balance, after containers and so forth that can be readily used, into a recycling system that significantly ends up in a landfill.
For example, my municipality only actually accepts 1 and 2 plastic in a recycling bin, but if it was being used for power generation maybe all of the numbers could be in there excessive 1&2 and all of the 3-7 go to the power plant? I'm not sure.
Right now if 3-7 are in there they just have to be landfilled.
The person doing this needs a bicycle pannier. If you account for the pannier that did not get made from scratch, surely reusing these cans/buckets has to be a win.
The mining/drilling energy overhead is already embodied in the material, so it may be better not to waste that by burying it instead of getting some useful energy out.
The plastic container diverted for the bicycle pannier market isn't likely going to do anything to dent the flood of plastic waste.