I think that it can still be useful with some things. However, recently, I've been limiting my reliance on gems outside of what Rails has provided. I'll still bring them in as needed if they are accomplishing something that either Rails doesn't offer or brings much developer happiness. For other gems, like simple_form, I likely wouldn't develop a new application with it anymore. Part of my reasons behind this is because I've upgraded many Rails applications with newer major and minor versions. The ones that were easiest to upgrade were smaller projects with just a few gems. A few gems that I don't have issues bringing in are friendly_id, devise, pundit, devise, and kaminari (however I may invest in pagy now instead). Over the years of upgrading apps and with what Rails offers today, these gems have been pretty solid and well maintained. Beyond these, I would really think twice about brining in a gem. For example, something like simple_form as you mentioned can be accomplished with form_with. Something like cocoon can be accomplished with StimulusJS.