I think it would be ok if the older version gets e.g. much better battery life out of the device This as an argument I heard for using older android versions f

I think it would be ok if the older version gets e.g. much better battery life out of the device This as an argument I heard for using older android versions for low end phones around 50$, because newer versions run horrible on them. I'm not enough into mobile phones to judge whether this is true, but OS version is a tradeoff I would be willing to make dependent on what I'm looking for