Now how is it that routine is for endurance?

Agreed. And I think endurance is the wrong word here. Lifting weights for strength and muscle mass I understand, but endurance? If I wanted endurance I'll start running marathons.

the reason for barbells is because you will soon outgrow the db weights for squats and deadlifts. how often do you come across 50kg dbs?
im assuming you're not doing goblet squats, db squats dont give much ROM, and your grip -will- be an issue later on.
you can generally bench heavier with barbell compared to db's, because you dont have to stabilise the barbell so much. its just a matter of pushing it up hard enough.

okay, muscle endurance then, but the thing is, im lifting weights to get bigger and stronger, lol. doesnt really matter if i can squat or curl 50 times, its not gonna show in the physique right?

100kg x 10 x 10 deadlifts GVT style hmm.
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nah, lol.

dude, no one can tell you if you're feeling tired or not. still felt you could go on? do more work then. why stop just because your planned routine ended? use more weights, do more sets, do more reps. do whatever.