A Magic Eraser taken to any paint film is going to remove some of the final finish. Magic Erasers are good for lots of things but should never be used on a painted wall IMO. When light hits the scrubbed spot just right, you can see how the Magic Eraser left an uneven finish behind. SuperPaint is honestly one of the best values on the paint market today. Value meaning you get a lot of good stuff in the can for what you pay. Including a perfectly lovely final finish/result. Especially if you hit it on a sale or have coupons. But Super Paint is not a top tier can of paint. The more upper tier, better grade of paint you go, the more durable. Usually. In general people take the notion of "scrubbable" too far with all tiers of paint. Better grades are going to be tougher, but they have limits. You can only clean within reason. There is a breakeven point where you have to objectively look at the ding or scuff and determine it needs to be touched-up, not scrubbed.

I don't know which SW is the best for you, but I am also researching white paint for my cabs. I suggest a Google search of best whites or best SW whites for cabs. I found great info as to why you should pick a particular colour (it's all about the undertones). I am leaning towards BM Simply White, but your preferences and your space may be very different than mine!

Let the professional pick what they like

Ask the shake manufacturer for a color match, and if they don't have one, as for a sample of the fabric. Take to SW and get to run it under the color analyzer.