This is my take on the subject.
Although these courses can be very helpful as a starting point in learning the techniques, posing tips, and lots of other stuff, when it comes to wedding workshops in particular I personally don't believe that those shots should be used in any portfolio used in an attempt to get paid work.
The reason I say this is the shots are all set up for you, with a stunning looking "bride & groom", in a stunning location, and those same shots will have been taken by everyone on the course.
Hardly "your own work".
I'm not saying that is what any one here is going to go and do, but I have seen entire websites of "amazing wedding photographers" whose portfolio is composed entirely of workshop shots taken under ideal conditions.
By all means do a course or 2, and learn from them, but then go and second on a few weddings. This is when you start to really learn.
Ugly bride, ugly groom, ugly venue, ugly weather.
Make that combination look good on a website, then you can say it's your own work !
That's a lot more difficult than a course.
Of course these courses are good to learn from, I've done couple of wedding courses, and learnt lots.
I enjoyed them too.
But for me to use those images to get paid work would be fraud as far as I am concerned.
< OK, Rant over >
For portraiture, I went on a few meet-ups with a hired model or two, and learned from the others on the meet. Cheaper, and good fun too.
Just my opinion of course, and I'm sure some will disagree.