There are many ways for a spiritual guide to come across. One is if they try to live up to some image, which either is due to a lack of clarity or (possibly sometimes) a skillful means. The other is when they use their own life, with all its messiness and shortcomings, as examples for universal challenges and ways to relate to and work with it. And of course, there is the tendency for students to somehow create an image of how a guide should be, and an overlay of how a particular guide is.
All this messiness seems to be another reason for a teacher to be as transparent as possible. To lay it all out there, all the messiness and hangups and everything else. It (hopefully) helps puncture some of the ideas students have. It helps offer examples for how to work with the universal issues that comes up. It helps students see that they too can do it.
Especially in our times and culture, which does not take to old fashioned systems of authority very well (for good reasons), an approach of full transparency seems useful and appropriate. It may also help democratice and demystify the process in an appropriate way.