But did it make them more productive?

Oh it does... but what happens after 6 months is an entirely different story.

A codebase that has exploded in size 2-3 times in just a few months,... internal architecture that is not layers of simple parts anymore, but, layers of complex architectures corresponding to individual agentic runs,... a codebase that now has 10 times more if-else and individual codepaths because you were not clear enough in your requirements, and used the phrase "handle all cases",... a codebase that neither you, nor anyone else now understands properly, thus, can't comment on what's possible anymore, and and at what costs when your manager or PM asks,...and finally, due to combined effect of these, a need for an ever increasing token budget, and constantly increasing fragilty of new AI-generated code due to repeated context compactions.

And we haven't even touched on the security and performance elements yet.

The right way to use these tools is to use them as, what I like to call, "code-monkeys". You tell them exactly what you want, where you want, how to do it, and how to architecture it, and more.. and then make them code.