So his 59 is a delofted 60 so taking bounce off (pity we couldn't see that figure in the video) what would be the advantage if any over lofting up a 58 assuming the required bounce could be achieved?

You've kind of answered your own question there, strengthening loft will reduce bounce and weakening the loft will add bounce. The desired bounce paired with availability of different grinds (not an issue for tour pros) will determine whether it's preferable to strengthen a higher loft club or weaken a lower lofted one. Coincidentally I have a 54m bent to 55.
Having said all of that, for the general consumer (including myself in this) - 1 degree probably doesn't make a great deal of difference particularly when you consider manufacturing tolerances (although Titleist's are some of the tightest in the industry) and the fact that very few club golfers get regular loft/lie checks to uncover any bending that's occurred through normal usage.

Really interesting, thanks for this. Another Pro using mb's!!!

Great video very interesting.

I have delofted or increased the loft, on a few wedges over the years to make them suit my distances.

get watch, really enjoy listening to the pros talking us though there bags.

Thomas Pieters was another good watch.

cheers for these TT and keep them coming.

maybe a Justin HARDING one would be nice since his win.