Many of us audition music to make sure it's a stylistic match.I guess I'm different than others here...I don't buy anything unless I hear it once and KNOW I'll like it...
I also check the Internet as much as possible to see how others rate the mix if it's in 5.1...but usually mix quality isn't a factor in my buying decisions...only the actual music!
A free trial download might be welcome for multichannel, in the case of engineers with non-existent or dodgy track records. But time has an opportunity cost. The more I'm downloading this or that for audition purposes, even if free, the less time I have for other things. Like arguing here!
But the original question was about paid downloads, anyhow!
And, to each their own. I have no issue with people who like or prefer downloads.