TL;DR: Is combining weights and cardio within the same exercise unwise or unproductive?
This video talks about cardio during weight training and describes how combining the two in a certain way can help the goal of maximising fat loss, specifically:
PHA incorporates an element of cardio into your weight training routines by forcing your heart to work harder.
This video, however, talks about HIIT and Tabata (albeit briefly) and criticises the use of strength training combined with cardio, specifically:
Be singularly focused; If you're trying to train for strength - train for strength; If you're trying to train for cardiovascular ... then do that, but don't try to combine the two because it becomes just stupid in the long run.
I am not sure if the second video is saying that the advice in the first video is actually wrong or if it is simply saying "do that type of training properly or don't bother."
I am not referring to this or this because I am asking if the two types of training should be used within a single exercise set at the same time at all, rather than on different days or for particular timings within a gym session.