The guy wire technique is used both in landscape trees and bonsai trees. You’ll often see trees that have branches with wire attached to them anchoring them downward. The wire is used to put pressure on a branch and hold it in position until it sets.
This is an extremely useful technique. There is a branch size limit to which a heavy wire gauge can bend. Also, having too much wire on a branch is not attractive and will take away from the overall appeal of a tree. Guy wire can be used with as a little as 2mm wire for a strong hold. When done correctly, it can be used to bend branches that are well over 3 inches in width.
The use of this technique with raffia will allow you to bend thicker branches much easier and with more confidence.