well, the way the impermanent loss could be bad is if the DEC vs BUSD goes down.
Say you put in 100 BUSD and that made you put in 100000 if the peg was 1000 DEC is 1 BUSD and then over time DEC peg drops to 1000 is only 0.8 BUSD. Then you need to look at this chart.

This is the rule for LP as your assets move you can lose money. Now the higher price part of this chart doesn't matter for DEC pair as it will never, in theory, go over 1000 to 1 BUSD by more than a little but still in that case as it goes up you lose a little bit because you would have been better just hold dec but you do gain money just not as much if you just held it.

I put a few arrows at around that lowest I see DEC for longer times 1000 equal .70 BUSD. That little area is you lost is only a few % points 5% at most I think but could be off by a little so if DEC fell down and you went to pull that same 200 dollars out you would only get %190 dollars and it would be more DEC and Less BUSD. Hope that helps a little.