Summons really lack any use in terms of dmg later on. And from the values the TE posted I am rather sure he does play on "Explorer Mode".
I'm on tactician
The normal damage values for bone widdow are kinda low and the hp is also not this high.
I'm not making this up
https://imgur.com/a/0dmN9 the lack of magic armor is nothing against having four times the HP and twice the armor, if you cast power infusion and teleport on the incarnate you will spend 4 AP instead of just 3, still have only 1/3rd of the total hitpoints and deal 100 less damage.
Saldy I can't post any screenshot because I am not the host of my mp playthrough.(they really should make the chars bound to the account like in Baldurs Gate/NwN etc. not to the savefile. -.-) We have 2 ppl using the bonewiddow and tbh it never feels as useful as an elemental.
4x taunt and 4x extra knockdowns/heals/ae spells are just way better, at least in our setup.
And you summon and infuse them pre combat. If you play in mp you don't have to wait for spells from other chars. Everyone can just summon everything at the same time.
Edit: I was rather shocked when I started a sp game that you just can't switch to another char and summon totems/pets right away like in mp when everyone summons at the same time. You really have to wait until your first char finish his spells until your second/third/fourth char can summon his totems/pets. oO
With 4 players this ends in 4 summoned and fully infused incarnations/champions and around 12+ totems before the combat even starts. :p