The best use of RSS is actually this specific use-case, -compiling a feed full of sources that do not publish regularly. Nowadays, between Twitter, aggregators like Hubksi, Reddit, HN, etc, and even "dumb" aggregators like personal magazine apps, it's completely out of the question that I will fail to be exposed to any story of interest to me that is published in any of the medium to large outlets.

An RSS feed comprised only of interesting sites that publish irregularly is a goldmine. I can't really think of another way to make sure to capture those posts. Even bookmarking doesn't work, as you fail to follow up. RSS is great for this.

If Hubksi does this it needs to balance the weight these posts would receive in your main feed. You'd have the way most people use it (incorrectly imho), -following large and medium websites vs. using it well, following sporadic publishers of quality. Might make the most sense to make followed domains separate from the main feed in some fashion, or risk losing those rare posts in the noise with an algorithm that mitigates the firehose that results in somebody following wired.com or whatever.