1 is functional isometrics 2 is overcoming isometrics
Both are fairly similar in that they have their greatest impact on concentric strength (whereas holding a weight art a point in the range of motion is best for hypertrophy and eccentric strength).
The former is a bit superior especially when it comes to learning to "beat the sticking point" because its dynamic structure is similar to a sticking point (dynamic phase preceding the stoppage of the bar). It also has a slightly better transfer to concentric strength and has the advantage of being more measurable.
The later has the advantage of being less neutrally and energetically draining.