> Objectively speaking, what advantages does it bring?
Lack of random crashes due to memory corruption.
Lack of data corruption due to undetected memory corruption that has been written to disk or the network.
Yes, these numbers for any individual user are quite small. But the definitely happen. If you have crash metrics for a client application you can see a very significant difference between ECC and non-ECC users. Some of this can be explained by general hardware quality but it is undeniable that having memory that randomly has errors is a real problem with adverse effects.
Objectively speaking, what advantages does it bring?
Objectively speaking, what consumer laptops offer it?
Subjectively, given that it's rarely supported by consumer laptops, why would it be justified to dismiss a device without it as a "toy"?