No! Express is a cool library but it shows its age. From the very beginning the aim of Marble.js was to build it from scratch with its own philosophy in mind. Thanks to the design decisions that were set at the beginning of its existence, Marble.js is faster than Express and comparable to the most performant HTTP libraries available on the Node.js platform.
There are many alternatives available on Node.js platform. Marble.js defines a uniform interface for asynchronous processing of incoming events, which makes the processing easy to adapt to different forms of transport protocols. Marble.js fits best in event-based architectures, like: CQRS, Event Sourcing or microservices, but you can also build a CRUD-like systems with ease without touching previously mentioned concepts.
Despite the single event nature of basic HTTP, there are no contradictions against using it for single events, like in HTTP. In Marble, RxJS is used as a hammer for expressing asynchronous flow with monadic manner, even if you have to deal with only one event. Marble.js doesn't operate only over basic HTTP protocol but can be used also for both WebSocket and event-based messaging patterns, where the multi-event nature fits best. Don't be scared of the complexity and abstractions presented in RxJS API — the Marble.js framework, in general, is incredibly simple.