Is "broadcast segmenting" still relevant in 2018?

We've all learnt that you should do VLANs and whatever to separate different networks with VLANs, because of the broadcast traffic.

However, in 2018, is this still relevant? From what I've understood the newer OS versions don't really depend on broadcast traffic that much.

So what kind of real problems someone could experience running something like /19 network with all kinds of different devices in the same VLAN? Something that has been proven and not just something that's in the Cisco Press books.

Point being that if you just do a basic L3 switch with different VLANs you're not separating your networks security wise, just broadcast wise. Unless you do VRFs/ACLs