What finally got my wife's visa approved, after being rejected twice, was we gave them a (truthful) sob story about her needing to accompany me to the US for an operation. They gave her a tourist visa valid only for 6 months to accommodate that, and then the next year she applied for a tourist visa again and they gave her one that was valid for 10 years. That was back in 2013.
However if your plan is to use a Green Card as if it's a multiple entry tourist visa (without actualy moving to the US), that's technically fraud and could cause her to be denied entry to the US at some point.
for people who meet the minimum financial requirementz, Green Card applications sometimes have a greater chance of success than if applying for a Tourist Visa because the American spouse's particulars are carefully examined when applying for a GC. When applying for a tourist visa the spouse is generally not part of the process.