I like Unilateral strength training for golfers for a number of reasons.
Strength & Stability
(Can be) Nicer for many peoples joints
The video here demonstrates some lower body unilateral strength training exercises.
Firstly, using unilateral strength exercises (for upper or lower body) can help reduce asymmetries from side to side. Often people are stronger one one side of the body can help reduce these. It would be the similar idea to using dumbbells for the upper body during a bench press (instead of a barbell). Not that you will have exactly the same strength each side, but it's important for injury risk and performance that we are somewhat balanced.
Next, unilateral exercises can be great exercise to focus on to improve strength. And it helps stay away from becoming as powerlifter and focusing on Squat, bench and deadlift (not that there's anything wrong with that some of the time, for some people). For example the Split Squat can be a great exercise to progress through a programme.
E.g. 10 weeks of split squats increasing volume and then intensity
week 1 - 2x10
week 2 - 2x12
week 3 - 2x15
week 4 - 3x10
week 5 - 3x12
week 6 - 3x15
week 7 - 4x10
week 8 - 4x8
week 9 - 4x6
week 10 - 4x5
Unilateral exercises can be more demanding within the frontal and transverse planes. Most people may stick to sagittal plane movements in the gym as these often allow us to move the most load. But even sagittal plane exercises like the split squats or lunges require more strength/stability in the frontal plane compared to a bilateral squat.
When using unilateral exercises, they can often be nicer on peoples joints compared to bilateral exercises. For example, you might choose a split squat instead of a squat to reduce the load on the lower back. Sure, you could do a barbell split squat too (similar to a barbell back squat), but the load would be lighter on the split squat.
As with all training, you need to choose the best options for yourself. This could change at various times, but its about knowing options that you can choose from. And obviously can include both, unilateral and bilateral exercises in your programme.