Personally I think the best thing about this is that it is throw away. That should be your usp.If you can get quality that will last a few mixes at a good price, I think it will work.
as for other trades.
plasterers and bricklayers will not spend any money on tools. Plaster doesn't go off and stick like rapid set. Bricklayers just use a bucket to put their entire collection of tools in.
plumbers ( me) do not mix much, and if they do they just chuck the bucket.
i think there's more possibilities to this, i.e. Food manufacturing, where they mix products in buckets and need a clean liner each time.