[KirinDave]

Yes, but the domain of your computer memory is surprisingly disjoint from the domain of your business logic, and that's really what matters here.

Consider a counter-example, where calling a functional method that takes an object and creates a copy with a new field updated (a classic pattern for introducing immutability to a mutable environment). What if internally the constructor calls a log call or increments a shared resource tally?

Not unreasonable, but in a functional context an update now has weird side effects that creates misleading results.