The trouble with a static sheet
You find a guest list template, download it, type in everyone you might invite, and feel organised for about a day. Then the replies start arriving, but they do not arrive inside the sheet. They arrive in texts, in a group chat, in a voicemail from an aunt. Now you are copying answers across by hand, and the file is out of date every time you close it.
The real cost is that you end up with two lists: the template, and the messy pile of actual answers, and neither one is the truth on its own. A guest list that collects replies into itself removes the copying entirely, because the list and the answers are the same thing.