In reply to Wotcha:
That way of tying the clove hitch can be useful, for example when getting sorted at small, restricted stances. An Italian hitch can be done in the same way, although I've never needed to.
The one-handed bowline is less useful, although it's not hard to think of unlikely (but not impossible) scenarios where it would be handy - hanging on with one hand after an unroped tumble (with no harness on) part-way down a cliff, for example.
Neither method is difficult - easily learnt with a few minutes practice. However, most climbers can't be bothered, which is understandable.