hourly rates are used in all sorts of businesses for estimation and also
for charging on jobs where there is uncertainty in scope (and the
customer is willing to accept the open ended risk) -- if there is trust
between provider and client then it works well, prevents the provider
from 'padding the cost' to cover him/herself, otherwise it may well
become a platform for abuse
Agreed completely, jjss49. I had a complete kitchen rehab done by a remodeler who worked by the hour. Of course, I had experience and trust with him. Lower pressure for him, in an unpredictable older house, and I didn't have to pay extra for his "surprise insurance."
And of course, hourly rates can be useful for comparison shopping when the the temporal parameters of a job are pretty well known, as in the case of sokogear's example of grass cutting.
Bottom line: the hourly rate is not the bottom line, but can certainly be information useful information in shopping and assessing value.