It saves a whole keypress (because you need to go into multicursor mode first, then press Home / Ctrl+A to get to the beginning of the line.
Additionally, there is a case where if you don't select the last line until the end, you end up in a state where the last cursor is already at the beginning. If you press "Home" now, you end up having that last cursor at the beginning of the line - and the other ones at the indentation level (see https://github.com/Microsoft/vscode/issues/14919#issuecommen...)
(Disclaimer: Author of the mentioned plugin, so I am heavily biased against my own workflow and saving-keypresses-obsession :P)
Additionally, there is a case where if you don't select the last line until the end, you end up in a state where the last cursor is already at the beginning. If you press "Home" now, you end up having that last cursor at the beginning of the line - and the other ones at the indentation level (see https://github.com/Microsoft/vscode/issues/14919#issuecommen...)
(Disclaimer: Author of the mentioned plugin, so I am heavily biased against my own workflow and saving-keypresses-obsession :P)