Having no meaning in itself, it seemingly is either a bridge to something else, or a pause for reflection (?) or continuing a thought. Sometimes it seems to be an attempt to keep the listener tied up, for whatever reason, and then there is a kind of stylistic twist, especially for younger conversationalists and/or those influenced by them. Thus it is almost colloquial in a sense.
While studying and attempting to speak Spanish years ago I noticed a similar use of the word "pues," which means well in the sense described above, thus as a kind of semantic stopgap, and I found myself using it as kind of a language crutch. At the same time, I noticed very quickly that using it in class or in serious conversation was frowned upon.
In checking in my dictionary I found that the word is not to be used as a conjunction, in proper usage; and this book was published first in the late sixties. It might be instructive to see what a present day dictionary would advise. Whatever that may be it will probably not anticipate the next overused or misused word to enter and dominate the English language, like .....