Speaking from experience, if you only need rudimentary L7 load balancing, then Cloudflare Workers is as good as it gets.
> How much are you paying for the workers/month?
Per my estimate, probably between $600 to $2000 for Workers: https://news.ycombinator.com/item?id=34639930
What would you do in Workers that you couldn't do with Load Balancing? LB handles origin health, can do traffic steering, session affinity etc included. With Workers, you'd need to take care of all that.
I see a point if the Workers do some lifting / caching / transforming etc before passing on the requests, but as a simple load balancer, the actual Load Balancing service seems a better fit.