We did consider it but decided to aim for simplicity first by not carrying both concepts simultaneously.
From what we’ve observed so far, while there are cases where it might be helpful, they are somewhat rare and people do discover that @'ing to disambiguate works pretty well in these situations.
Another idea that has come up a few times is to support quote-reply within chat. We’ve opted not to do that yet for similar reasons, but it’s something I occasionally wish existed (and I do reach for > to work around this, but my experience is that few people bother, so I think providing a greater affordance for quote reply would be necessary if it were a behavior we wished to encourage).