Yes, a good bonus of change of gauge flights is that you double-dip if you misconnect. I was once on AA 89 BRU-ORD-LAX, which had a plane change. Misconneted ORD-LAX and was rebooked. So I received BRU-LAX and ORD-LAX miles.

Another advantage is for using international upgrade vouchers, such as UA's service checks which are good on one fligth number only. Was able to use one of those on UA 862 SYD-SFO-JFK ....reservations wanted to only upgrade me on SYD-SFO, but the rules on the certificate said it was good on a single flight number.