When you examine the Get-Bios.ps1 script, you can see that it does not receive any input from the command line. This is a good way to avoid user errors in your script, but it is not always practical. When your script accepts command-line input, you are opening the door for all kinds of potential problems. Depending on how you accept command-line input, you may need to test the input data to ensure that it corresponds to the type of input the script is expecting. The Get-Bios.ps1 script does not accept command-line input; therefore, it avoids most potential sources of errors (of course, the Get-Bios.ps1 script is also extremely limited in scope—so you win some and you lose some).