In vitro multiplication of J. sobolifera

It is hard to say from a black and white photograph of a plant grown in a laboratory, but to me it looks more like S. tectorum or perhaps S. montanum or a hybrid. The article doesn't mention the source of the plants, but like you I doupt that it is a Jovibarba at all.

The argument that in-vitro propagation is helpfull for conservation of rare houseleeks could be valid in case of plants which form very few offshoots naturally, but hardly for Jovibarba sobolifera which is generally very easy to propagate. In this case I would think of monitoring population status, perhaps some habitat management and if needed setting up a backup collection in a botanical garden.

I think that this mainly has been a valuable practical experience in plant propagation for the researcher (student?) and perhaps might lead to interesting further research. I woudn't dismiss it, but some more critical notes might be added ...