So a locker you have to physically engage it. Such as turning the hubs of an old jeep?

And to be honest the factory LSD's aren't very tight in the first place.

The lockrite locker puts 100% power to the wheels at all times ONLY when you have your foot on the gas. A selectable locker only puts 100% to the wheels when engaged (either engaged by compressed air or cable, etc.).

I'm interested in situations such as being backed up with my tires half underwater on a steep boat ramp trying to pull a trailer out of the water. At that time I want both wheels turning. Or if I get into some snow and start to get a little stuck. It would be that type of instance. I assume a LSD would be sufficient in those situations generally speaking? Which would be few and far between compared to my regular driving habits.

If you're going to be relying on the fact both wheels are turning, I would go with a locker personally.

Though you can modify a factory LSD and make it act like a locker by adding more clutch packs, but that makes your rearend locked all the time.