Yes, the Siberian is a suitable anchor knot for many applications. Youtube has some videos of using it as an anchor in camping applications.
Where a Siberian can be used, however, I find myself using a Slipped Buntline, a Timber, Sailor, Girth, or some sort of fixed loop. I'm not totally comfortable with how the Siberian opens up on large diameter objects. It remains secure in that form, but I figure there's no reason for me to deal with my discomfort when there are other hitches that will remain true to form.
Regarding the Trucker Hitch, I agree it is a fantastic substitute for a Tautline, a Blake, an Adjustable Grip, etc. I strongly prefer a Trucker Hitch because it's easier to adjust the tension, easier to release, more secure, and easier to get more tension. Minor disadvantages of a Trucker are that it requires a bit more rope, more forethought, and more practice to tie it correctly and quickly.