The weaker a draw is, the more it moves along the sliding scale from semi-bluff to bluff. These are the kind of spots that can easily become very situational in poker, hence our decision not to include as many of them given that they are less transferable in general (and overall quite a bit less important than the more profitable check-raise spots with strong draws).
For example the backdoor draws, in order to check raise (instead of a default fold when not getting the correct odds to continue as would often be the case with the weak draws you mentioned), I would want to see that my opponent had a very high c-bet % as well as a high check-raise % over a significant sample. If I see that info and opt to check-raise, then that play is really more about exploiting my opponent's leaks than it is check-raising as a semi-bluff (having a shot at a draw is really just something extra to go along with what I essentially consider to be a bluff at that point).
In very general terms it will be unprofitable to default check-raise weak draws, so that should not be the norm--and why there weren't nearly as many examples of this as the profitable check-raises with strong draws that we sought to emphasize in this section. Hope this helps