I don't understand the trend for these crosses but they seem really popular. My mum spotted someone advertising for a lab. x collie puppy ie. looking for one. Maybe there are plus points for them.
Hybrid vigour and a whole lot less snobbery.
I know that crossing two breeds doesn't guarantee no inherited defects but as a generalisation it is likely to reduce the probability and/or severity, especially if the two breeds have different inherited problems.
And whilst crossing two breeds could result in an individual with the temperament quirks of both parents, it often gives the better of the two halves.
I had a lab x collie, and knew another, and both were good eaters and 'good do-ers', loyal, fantastic with children, energetic but not hyper, and clever. Both chased sheep, of course, but so long as the owner doesn't live in sheep country (neither of us did at the time), that can be managed!
Both had the lab double coat, which was a bit of a downer. (Intentional pun - couldn't resist
)