Comment by KronisLV

> Why not conduct a survey?

Large amounts of time before getting feedback, low percentage of people responding, not an accurate sample of all users (you will get signal from the loudest ones) and inaccurate data (biases in perception) instead of measurable reality. Not useless, but not a full replacement for telemetry.

> If it's a customer, why not reach directly to him?

Layers of indirection (and also the slowness of getting through them). You might not control the processes and approvals needed to do that in a non-startup environment. You will probably control enough of the app to add various technical solutions to aid you in collecting information.

> No one is talking about telemetry on your servers.

I am. Culture of not collecting client side data also often comes together with a culture of not collecting server side data properly either. Competent teams will evaluate both. My argument is that all of this data can meaningfully help in development and that other approaches don't replace it well enough.