Anything the Republicans enact won't necessarily be undone and political capital has to be used to undo it. The gains here for democratic constituencies are so small as to be almost meaningless and there's a high political and fiscal cost to doing it.
Democrats aren't stupid, they won't take a deal this bad just because it provides some tiny amount of money to poor people. It will be easier to get a better deal in the future when removing the expensive tax credits for rich people won't be viewed as 'raising taxes'. In addition, if they can cause this plan to fail they will further weaken Trump's political leverage and increase their odds of winning control of one of the houses of Congress, at which point all conservative legislation stops.
So no, if you think refusing this gains nothing then you're just showing your own ignorance.