Por que no los dos

[Jessica]

Por que no los dos? is a Spanish phrase meaning why not both?. It was bastardised when first introduced to the English language from an Old El Paso advertisement, where a family of [mexicans] are feuding over the difficult decision of either having soft or hard shell tacos for their burritos.
The phrase has since become a frequent part of the Australian vernacular, particularly to [bogans] with limited knowledge in Spanish (such as myself), where por que no los dos? can be exclaimed in any given situation where a decision between two options has to be made.

In pop culture It’s a reference to the old El Paso hard and soft taco commercial, where the little girl says "Por que no los dos"

On other hand "Porque no los dos?" means "Because not both?"