Applications and the need for layer 2 adjacency

Hi everybody,

I'm somewhat new to the world of networking and I've been learning VXLAN/EVPN/ACI lately. I keep seeing that the big deal with VXLAN is that it extends layer 2 (eXtensible LAN lol) and that many applications require this layer 2 adjacency. I haven't found a great answer for it though.

Any help would be appreciated!