Some people don't want to understand that it's unrealistic to reproduce the original over 3 generations, otherwise you simply wouldn't add bx1 2 3. You have to practice to understand this, but I agree if you've screwed up or if your fetish variety is tired, even if I sincerely think, as people have pointed out to me, and this is where I'm 100% okay, that it's better to start from scratch and purify a line that might correspond to your wishes.People mainly talk down on it because MrSoul's math was off and you are nowhere near the 94% uniform true-breeding variety in three generations. But with more realistic expectations backcrossing is a fine tool to have in the breeding toolbox.
Yes, as a selection tool and to find something better to your taste, it's highly recommended, you could find some beautiful things, I've done it on cookie over 4 generations, waste of time! Vive les landraces Like a lot of other things I wanted to try that were in fashion
BX is often used in a misleading way, but that's my opinion.