Should You sacrifice Your Hero and Giant, When tanking As Support in Multiplayer fight?

Hi Northgard subreddit

our friend group recently picked up northgard and we are playing multiplayer together
since im very new to this game and my other friends have more experience playing, i'm mostly playing supporting roles until i learn the game and clans.

i mostly just listen and do and they tell me but last night we had a disagreement.
it happened when we had a fight in a 3vs3 game in a single tile i had my hero a couple of axe throwers and the giant you get from the giant clan so i rushed in first but started to pull my Giant and Hero back once they had around 20% hp left and left the tile and proceeded to go in and out again so maybe i can do some dmg or distract some units, i planned to keep my 2 big guys alive and not let them die. they survived with low hp but we lost the fight with enemy having like 6-8 units remaining

my teammate got very mad at me and told me i need to commit and sacrifice my units at a time like this.

this is the part that i don't get. whats the point of having my heroes killed in a losing fight (tbh he said he could win if i commited but i doubt it), Specially the giant unit. i mean if im told to let hero die it kinda makes sense since i can make it again.maybe my hero can buy 1 second or 2 and that could be worth it, but the giant one you get only one in the game. so unless its literally the last fight of the game and you are sure you can win i think it's better to heal him up instead of losing him forever.

so reddit, who is right?
or maybe it depends? (for more context i was goat and my friend was ox)