I was dreading a long queue wait or similar
That could still happen of course when you front up at the Extranjeros Dept!
In answer to your question…
For store purchases with a debit or credit card, your passport is all that is required.
If your debit / credit card is a Chip and Pin version most stores will accept the PIN entry in the machine as proof of identity; some stores however still require the passport. As an example however of the truly screwed up way some things go out here, Carrefour recently introduced an ‘Over Sixties’ loyalty card… my Chip and Pin debit card is all I need for the actual purchase but in order to take advantage of the Over 60’s benefits I need to produce my passport… SNAFU or FUBAR…?
Frankly the A4 sheet seems to have little relevance to anything or anyone! The only validity that I can see is that it carries a written version of your NIE number which is sometimes requested by utility companies or if you need to make a major purchase like a car. The cynics point of view and it is yet unproven is that when you register or re-register your information is supposedly passed onto the Spanish Tax authorities…
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