No, collecting information on how many times someone types the sequence "abcd" is a waste of resources. Figuring out what telemetry will be useful and understanding the privacy implications is important.

>Telemetry is a cheaper solution to hiring quality assurance.

These are not comparable. Telemetry is about understanding how the product is operating. QA is about testing the product.

The main downside is the extra work and cost of getting it all set up, properly cleaning up unneeded telemetry, and making sure telemetry itself doesn't cause performance issues.

>No concept of misleading info or bad product development direction from using it?

Telemetry doesn't replace a strong protect sense, but without telemetry you are flying blind.