yes, this is how is it designed (actually, this is the MMF (minimum marketable feature) for tags).
I don't expect the tags being reused too much. For example if some task is blocked, than you will make a tag with name like "B" and a description why is it blocked. The name would be re-usable, the reason not.
When it will start to be painful because the same tag will be reused in many tasks I may implement persistent tags, but I don't see to much reasons to do it so far...