"Microsoft has also closed its testing division which would probably be adding hundreds of millions of dollars to Microsoft's profits. This would have been impossible without the use of the telemetry."
In other words, users of Windows 10 (except for enterprise and educational users, who can turn telemetry off, and are the only customers that MS actually cares about) ARE the new testing division, only now they pay MS for the privilege rather than the other way round. The telemetry is important in a beta version, as it will report any malfunctions encountered during the testing-- particularly when the beta testers are novices that would not be able to write a sufficiently detailed bug report or to know what to do to obtain the information to put in the report.
Yes, you using your PC is "testing" now, Windows 10 users. When your PC crashes or loses your data, at least you will have the comfort of knowing that you've done a little bit to improve the product for the corporate customers that MS actually considers important.