Sure! I think it's just a question of scale and knowing your problem. If it's "the entire customer-facing area needs a large amount of interactivity" then going

Sure! I think it's just a question of scale and knowing your problem. If it's "the entire customer-facing area needs a large amount of interactivity" then going with a SPA makes sense. If it's "this particular UI element on the customer app needs a large amount of interactivity", that's easy to build as an isolated component regardless of the technology of the rest of the app. One thing that I'll always view as a smell though is "we don't need X now, but we might need X in the future, so we should adopt this more complex technology just in case". We've learned that lesson MANY times as developers, it's not any less true for front-end technologies.