Basic powershell script question.

I am trying to learn a bit about powershell scripts and have been trying to logically breakdown a script which includes this snippet.

$destFolders | Foreach-Object { Copy-Item -Path $Source -dest (Join-Path $_ $destFileName) }

If i was writing this from scratch i think i would write it as follows – why am I wrong?

$destFolders | Foreach-Object { Copy-Item -Path $Source -dest ($_) }