Why do you use Ruby, and not Node/C Sharp/Java/others?
Ruby is meant to be a very productive language. It does waste some server resources, but the biggest cost for any project, especially early on, is in development hours, not hosting. Hosting typically costs between one-tenth and one-twentieth of the monthly development cost. Using Ruby helps us build what we need quickly so that your idea can be tested and tweaked while using fewer development hours. Once product-market fit has been found and the business needs to optimize more for cost and less for time, moving to a different, more verbose, performant, and less flexible language makes sense, but that’s usually several years away.