Yes. 1BTC is still 1BTC. inferior currencies are much less interesting.
I often see people make this claim but it simply is not true. If that were the case then taxes would certainly be easier, but it isn't. $1=$1 but 1 BTC does not equal 1 BTC, at least in the eyes of the law. It's all fun and games to pretend that Bitcoin is it's own thing, but it isn't. I feel like people with this attitude are LARPing as Bitcoiners, but actually have no idea what they're doing, don't pay taxes, and likely don't even understand what Bitcoin is. I'd love to see the face of someone's accountant when they utter the phrase, "1 BTC is 1 BTC" as that is the sort of stupidity that people tell stories about to their friends over a beer and a laugh.
I always saw "1 BTC is 1 BTC" as some sort of hopeful saying. If the world decided to abandon fiat and accept crypto then 1 BTC would indeed become 1 BTC, as the value of BTC would be itself. Or perhaps all of crypto would be smaller parts of the bigger true currency and Bitcoin would be a part of that.