Chest supported, no momentum, all back.
Lead with your elbows and squeeze your blades, do not just yank with your arms.
The chest pad is the whole point here. It takes your lower back and any body English out of the equation, so driving the elbows back loads the lats and mid back from a long stretch into a hard squeeze while the biceps assist the pull. That makes this the row you can safely push close to failure, which is exactly where back growth lives.
For building the back, yes, and for most lifters it is more productive. The chest support means fatigue lands on your back instead of your spinal erectors, so you can train harder with cleaner reps. Barbell rows still have a place, they are just not mandatory.
Your arms are winning the rep. Loosen your death grip on the handles, think of your hands as hooks, and pause for a second with the shoulder blades squeezed at the back of every rep.
Yes, let the shoulder blades glide forward so the lats get a full stretch, then pull them back as the elbows drive behind you. Cutting the stretch turns it into a half rep and half the stimulus.
