All due respect, nothing is absolute. The techniques you've posted are aimed at woodworking, not bonsai. In bonsai, using this technique interchangeable with LS as a preservative measure is impractical. Some applications, especially with interior work on trunks, or with smaller trees can be iffy.
Your right there are no absolutes except taxes and death....I amend my statement to "WRONG".
Since were playing semantics ..... the term carving, wood working, shaping and a dozen other key words I suppose have nothing to do with bonsai as well? Shaping, preserving, adding a patina all have something to do with working deadwood, be it in finishing a hand made cabinet (made from deadwood) or the deadwood on a bonsai tree.
As the two techniques when used in tandem being impractical?...Bollocks! When these two are used in tandem, is when both techniques truly reach there pinnacle on both an aesthetic basis and a preservation basis. While doing the preservative thing...the combination of charred wood that has been brushed, along with the whitening properties of LS are unsurpassed in achieving a natural look that you would find in nature.
I was introduced to this technique on interior work of trunks were a brush, chisel or gouge would have been fruitless. A fine kernel of flame can have a far better effect than any other tool at times when reaching into enclosed areas.
No doubt small trees require extra care and the right flame kernel is paramount.
On pines and other conifers, I'd make say I'm a little less wrong in saying that it's mostly used as an enhancement technique rather than as a preservative. Application of fire on coniferous deadwood can "open up" the grain of the wood and when the char is scraped off, leaves behind more believable weathering.
I would agree, using flame on conifers is a wonderful thing to enhance the texture of wood, as well as preserving it. The technique is a multipurpose tool that can be kept in your arsenal.