like i wrote above i think paid editors can be really valuable when they declare their COI and offer suggestions on the article Talk page instead of directly editing the article  people who know what they hell they are talking about  VERY useful   but COI erodes trust in the encyclopedia and often causes scandal and damages the reputation of companies that do it extensively that is why offering suggestions on the Talk page meets everybodys needs  good up to date content can get suggested reviewed for NPOV and quality of sourcing and added by a volunteer that is how it can work well