If we're talking ongoing 0% on certain purchases (in this case, apple products) vs. a welcome offer, none.
And for those who want to finance Apple products regularly, this is a solid card benefit and it may be right for them--especially with the 3%. Same goes for someone who already has an Apple Card, when you consider the additional benefit not having a new hard inquiry on your credit report.
But for someone who would be opening a new card, if you don't fall into that category of person who would be regularly financing Apple products or spending some serious cash at one of the 3% cash back partners (remember most ApplePay transactions are really 2% with Apple Card), there may be better options.
For example, a new Chase Freedom card will give you 15 months @ 0% and $200 cash back when you spend $500 in purchases in the first 3 months. Cash back is always a flat 1.5%, but this also includes purchase protection and extended warranty (these features are almost nonexistent on no-fee cards today, AMEX even removed them from their Blue series). On an up-front Mac purchase, you're making out better on the 0% period and cash back. And personally, I'd take the cash back tradeoff, which is really minimal from a practical standpoint, for the purchase protection and warranty benefits.
To each their own, but Apple Card benefits are very niche in the grand scheme IMO.