That's a good point and it's understandable if it's a cause for concern, but there's not much we can do about it as far as I know since we write the results directly in your spreadsheets; and the add-on, once installed, is present in all your spreadsheets. We need your email address in order to manage your credits and verify your credit purchases through Google Wallet.

Most other add-ons require the same permissions, so I think the permission titles could use a bit of clarification.

All that said, this is something to have in mind and improve for sure.