enc0 does have counters in netstat.
netstat -I enc0 -nWb -f link
Name Mtu Network Address Ipkts Ierrs Ibytes Opkts Oerrs Obytes Coll
enc0 1536 <link#5> 708 0 61014 796 0 61728 0
It's probably not in the MIB for some reason. I opened a feature request ticket.</link#5>