Edit: asking a question == downvote. I never said it wasn't a problem. Spending more time on lobste.rs anyway, this place is declining at breakneck speeds.
Then again, since you set the challenge - lamb and Iamb
I can see no good reason for us to ever use the same symbol to represent two different letters, that's just silly business.
Edit: for the record, I didn't downvote you. Interestingly enough, I just noticed that it looks as though I can no longer downvote direct replies to my comments. Seems like a reasonable rule to have in place.
The most common issue is hand-copying a piece of text between devices, such as a cryptocurrency address or a URL. Sure, it would be great if those sorts of non-linguistic bits of information were always tagged appropriately such that they show up in a different font, but that rarely happens in reality. Even here, on Hacker News, we can only talk in plaintext with a few minor markup features.
A general-purpose web font should be able to handle a variety of linguistic and non-linguistic strings and not choke up on edge cases. In that respect, I really like the differentiation between a capital I and a lowercase L in Clear Sans, no matter the inclusion of 'Sans' in its name.
(lo, as in a lota; lambic, as with an Iamb.)