Pipeline as parallel command

Normally, pipelines in Unix are used to connect two commands and use the output of the first command as the input of the second command. However, I recently come up with the idea (which may not be new, but I didn't find much Googling) of using pipeline to run several commands in parallel, like this: command1 | command2 This will invoke command1 and command2 in parallel **even if command2 does not read from standard input and command1 does not write to standard output**. A minimal example to illustrate this is (please run it in an interactive shell) ls . -R 1>&2|ls . -R My question is, are there any downsides to use pipeline to parallelize the execution of two commands in this way? Are there anything that I have missed in this idea? Thank you very much in advance.