Yes, it's treatable with antibiotics and people that are treated get less sick. As stated in the article, prophylactic treatment with Doxycycline is the standard of care. Testing the tick is an alternative to that rather than something that should be expected to increase treatment...

The article also mentions that symptoms sometimes persist after treatment with antibiotics.

Absolutely yes, because the most severe risks are associated with the bacteria reaching the heart and into the nervous system, which is a relatively slow process. There's a window of a couple of weeks.

If you could know as soon as you were bitten whether there was any risk of infection at all, that would be very valuable information.

I think it's only a one in ten chance that an infected tick would transmit the infection, anyway. But you would know whether you needed to even book an appointment.

Yes, but this test cannot diagnose Lyme in humans.