Expertise
Node.js for services where the JavaScript ecosystem brings a real advantage
Node.js is worthwhile for certain real-time services, I/O-bound processing and tools that share skills with the front end.
An architectural choice, not a matter of comfort
We do, however, assess CPU load, operations and the ecosystem before using it. Using the same language everywhere is not, in itself, an architectural reason.
A real-time service to design?
Describe the expected load and data exchanges: we will see whether Node.js is the right tool.