Are torque wrenches worth it?

What you are actually trying to achieve is a certain level of bolt elongation.
True. Thank you for mentioning that. I just did not want to get into the discussion about load et al, to which it will inevitably lead us and which just gets a little too complicated (well, at least the calculations thereof goes right over MY head), and it really does not assist in evaluating the price value of torque wrenches.