Twitter is a one-in-a-thousand company with traffic amounts that most of us here will dream of ever achieving. Even the more people that don't take specific interest in running large scale deployments.
Even writing you frontend in Java first would (most likely) not have helped you coping with the new-found challenges in that heights.
Twitter is a one-in-a-thousand company with traffic amounts that most of us here will dream of ever achieving.
And not every low-traffic site is simple CRUD. If you do image processing, applying machine learning, natural language processing (or a thousand other things that are CPU intensive), it's nice that you can directly use one of the many high-performance libraries available in the Central Repository in your webservice.
Even writing you frontend in Java first would (most likely) not have helped you coping with the new-found challenges in that heights.