[zzzcpan]

It depends, whether you are talking about common popular programming practices. In which case if a library can run as a separate service putting it into a separate process improves reliability, security and performance, as you can run it through a supervisor, limit its memory, cpu, monitor it, automatically restart it when it becomes unresponsive or dies not affecting as many users and not bringing down entire systems with it, update it when needed, more easily isolate and address performance issues, explicitly design and think about new trust boundaries that come with it, etc.