But those rules-of-thumb that became very popular through people like TPG are just stupid.
The value you are getting from a hotel stay is not equivalent to the cash price of the room. But that's the assumption underlying the rule of thumb. Classic case of "crap in, crap out" (am avoiding the expletive usually used in this phrase).
I used to do exactly what you described. Then I realized I spent too much time picking hotels alone and I value my time too.