The way around the Oyster card not in Apple Wallet would be to have the Citymapper Pass. It is a subscription, but so is Oyster if you use it for weekly/monthly/annual Travelcards.
Also, whilst banks can put limits on contactless/Apple Pay use, so can stores. When contactless first came out, the limit was £30, but that restriction doesn't apply anymore. It's up to the stores to update their terminals, which they rarely do.
I'm glad that Nectar and Boots finally has an Apple Wallet card, as trying to scan from their apps was terrible. I hope Nando's does this soon as there still is no barcode in the app and you can't even get the number if you have no 'net connection.