By the time 3to2 came out, the community had already figured out that it is a better path to right code that runs under 2 and 3 rather than using conversion too

By the time 3to2 came out, the community had already figured out that it is a better path to right code that runs under 2 and 3 rather than using conversion tools. Conversion tools are mostly a relic of when everyone still had to support 2.5. Once you are 2.6+, most people settled on single source as the best approach.