Personal trainers can easily find themselves trapped in two distinct and opposite modes of operating.
First, there is the kind of trainer that keeps things a little too simple. They look great and have the kinds of physiques that many people would want to have. They are friendly, have bright personalities and, while they have positive intentions for their clients, have no interest in anything of substance or value beyond the minimum effort required for certification. They often, however, do quite well at acquiring clients and tend to be the busiest trainers at the gym.
Then, there is the kind of trainer that goes deep. They pursue knowledge and courses on the sciences related to exercise non-stop, use a lot of technical terminology and hold a special place in their hearts for the pursuit of information over the delivery of useful information to those who needs their help.
These people may or may not have the look and dispositions of their colleagues in the former category.
Both extremes are tragic. The professionals best able to help the most people make themselves less available in favour of having their noses stuck in technical material. And, those least able to help obtain the greatest amount of business, sometimes (though not intentionally) worsening their clients' situations through thoughtless exercise advice.
Perhaps some sort of midway between the two extremes would be useful.