Hi @Mathvader. Either option can work.
I just finished a similar project using React + Middleman to run hydraulic force equations in the browser. It worked like a charm!
I’m building another page now, however, that uses a Flask backend because the calculation is more complex and I already have a tested, working implementation in Python. I could probably make this one work with Middleman backend + JS front-end too. But I reached for what’s familiar.
The benefits of Middleman over Wordpress have more to do with site security, page-load speed, and balancing complexity / capability. But if you already have a good wordpress site, I wouldn’t switch.
If this is a blue sky project: try Middleman! It’s easy to get started. And you’ll know shortly if it’s the right fit.