There are some users who, in the past, have questioned a moderators ability to moderate due to their lack of PhD.
I feel that this is quite irrelevant. During my time as moderator, there never came a time when my PhD helped me moderate. Any questions of scientific validity or off-topicness are dealt with by the natural peer-review of the site, with the answers and comments of expert users.
I think this is how it should be. Questions of science should be discussed out in the open where the maximum number of expert voices can weigh in. After all, the expertise of one or two moderators would not cover a whole field, especially a highly interdisciplinary one like quantum computing. Then this leaves the administrative matters for the moderators, as well as the personal and sensitive matters ones that need to be kept confidential.