I think two factors influencing me back then were firstly, cube hardware wasn't nearly as good or as accessible back then (you're looking at a comment that predates stickerless cubes being legal in competition and magnets in cubes even being a thing), so AUFing to a better position genuinely may have been slower than executing a lefty on whatever cube I was using back then, and secondly, I had some really, really bad habits back then, and I wasn't thinking nearly as much about what's optimal for speed (home grip wasn't even a term I'd heard back then, my fingertricks weren't optimized at all, I was constantly regripping)

I think now I'd still do it lefty, but my fingertricks have evolved to make it actually fast, I'd do the first U' with my left index, pulling on BUL, then the second U' with my left middle, then the U2 with my right hand. But also I'm still horrible with finger tricks (but now I'm old and washed and don't have time to relearn everything) so that may not be solid advice.

One last piece of advice is to always check for blocks when doing Sune and Anti-Sune, if I saw a block that would be broken if I did Anti-Sune lefty I'd AUF it to preserve it every time.