It depends a lot on how many players are in the pot. If you're heads up, pocket pairs are great. If you're at a full table (and I think your hand rankings are for a full table) you need to have a powerful hand at the end to beat all the others and suited connectors are good at ending up as powerful hands when they make flushes and straights.

A pair of threes lose a lot in a multiway pot unless you get a set.

I've done some simulations of 10-way pots (everybody at a full table stays in to the river). 33 is at the middle of the field there. JTs is hand no. 15 so it wins a lot more.

If you do the same for 2-way pots, 33 is hand no. 12 and JTs is no. 17 so a pair of threes is the better hand heads-up.