I wanna mention that I had some pretty good success with this. I chopped down my iced grapefruit girl and left literally one tiny 4 inch branch that got stunted during growth. I cut her down to the last node - no joke.
After about 2 weeks she was putting out new growth. It was taking up too much room so I decided to take the chance and clone it. I cloned it directly to soil...I've never had much luck with cloning and she got pretty significantly burned.
So another 2 weeks in or so, I thought I saw some new growth but I wasn't sure. I did this mostly as an experiment to see if it would work in emergencies anyway. I flipped the cup over into my hand and she did indeed have roots.
Its not really putting out much growth, but I haven't been paying her much attention. Shes in FF Ocean Forest right now and I checked those roots a few days ago. I'm thinking she'll make a full recovery eventually.
Its definitely not the best option, but if you have an epic plant that purples pretty extremely well, or just has awesome flavor/structure, etc...its certainly a viable method to save the genes.