Not even close.
Double polyethylene is insulated and holds heat much better.
A single layer greenhouse will increase you grow season, but isn’t efficient to heat.
In my opinion both have a place for growing.
A lot depends on your growing zone or what you’re growing for your needs.
This single Layer Greenhouse is $1,300 and if it was double poly it would cost about $300-500 more depending on labor costs.
My fully insulated greenhouse is about $3,000-$3,500 in materials, but it’s a post frame lean to.
You can go.
Cheap and use zipper doors.
It’s really whatever your budget allows.