There really wouldn't be any point in buying them, converting &...

There really wouldn't be any point in buying them, converting & then dumping them as you put it as you'd lose out in the 8% p.a. interest & unlikely to actually realise the 8% discount.
Don't forget there will be a tradeable market in these notes, all be it they will be very illiquid so you don't necessarily have to hold them for 3 years or convert.

The danger of these convertible situations is that someone gets hold of a lot of them & then shorts the share to depress the conversion price.
The risk in the next 3 years is a depressed share price because of that, not that you'll get fewer shares from a rising share price IMO.
I did consider selling all my shares & buying convertibles for this reason & probably would have if I wasn't sitting on a loss.