Heavy lance / LanceCouch lancing with these "short" lances is way more risky than thrust lancing with them due to decreased reach.
Furhermore thrusting deals more damage so there are quite 
few situations when you "should" couch lance.
I see no reason to change the couch lancing for these lances.
Build of Riddaren:
Level 35
Strength:21
Agility:21
Polearm:170
Weapon Master:7
Athletics:7
Riding:7
Iron Flesh:4
Power Strike:7
A big problem that I've mentioned like 10 times before is that it only needs 1 WPF in polearm to be 100% effective.
It's like you would only need 1 WPF in crossbow for maximum accuracy and reload time.
Sure, it deals high damage and has high reach but it has a fairly 
long cooldown and it requires more 
forward planning than using a heavy lance / lance.
Like with all classes, builds and play styles there are several skill levels.
This obviously includes the great lance or else I wouldn't be without any competition at the top.
I can't say it's easier than using a heavy lance or vice versa. It's just two different play styles.
If you think otherwise you just aren't at a high enough skill level. 
Build of Matthaus, the 1H / great lance "hybrid":
Level 37
Strength:21
Agility:21
One Handed:158
Weapon Master:6
Athletics:7
Riding:7
Iron Flesh:7
Shield:4
Power Strike:7