Moving on from net-tools

That's not quite a synonym. One of the many problems with ifconfig in this area is that it's outright lying to the user because its input and output formats are not flexible enough to accept or report what's actually happening. In this case, it's falsely claiming that there are two network interfaces, when in fact there's only one, with two addresses. ip(8) gets this case right (and makes it clear that you all the added addresses are peers -- there's no primary and aliased interface as ifconfig suggests there is.)