LOL. Okay then.

ER Infuse maintains Protective Bond on the full party, and uses up their Elite Slot to keep their energy up enough to keep it up. While also having the admittedly strong spells of Infuse Health and Spirit bond. They do, however contribute zero damage to the team, no buffs, no worthwhile attacks, nothing. I didn't even know players ran this for standard play, just throw it on a hero, dude.

As for it being "better" than Imbagon:

Protective Bond reduces all damage taken to 5% of the targets Maximum HP. A rough average of my Heroes' HP is 550, some a little lower, this makes it 27.5 damage.

A properly set up Paragon team will use shouts that reduce damage by a total of 92.5% (or 88.5% vs certain enemies such as Destroyers). Compare this to the 27.5 damage you'd take from each hit with an ER prot, you'd need to be taking more than 367 damage per hit for ER to function better than Paragons. Some Elementalist foes in Hard Mode can hit this, if they don't get interrupted, Bosses might deal a couple hits for this much damage but the majority of things hitting you wouldn't be anywhere near that high. Mesmer spells ignore Armor so their full damage will go through, but because they deal their listed damage they rarely go over 120 unless cast by a boss. Not to mention the other skills the Paragons can bring to increase the Block chance of all party members permanently, a nice QoL speed boost, health regeneration, Critical Hit Chance. You only need to use 2 Paragons for this, but you can use as many as you want.

You don't even need spike heals in PvE, especially when you've got this much PASSIVE defensive power, you and your heroes can spend your time doing damage, and you don't have to spend any time casting defensive spells because your shouts activate instantly. The Paragons will also be dealing Physical damage, while it's not in massive amounts, they can be buffed up by Barbs, Mark of Pain, Order of Pain, Splinter Weapon and more. Which, if you've not noticed, is how you maximize your DPS in PvE alongside Mesmer stacking.