Disabling the spellthief line when taking cs feels bad

I understand there are abuse cases where pro players use spellthief because it generates a lot of gold, but when my adc goes b or dies and theres a wave at the tower, i have 2 choices A) take the cs and lose out on spellthief stacks, which is better for gold or B) skip the cs which is loses me gold but gets me closer to the quest completing. Either way, i miss out on a lot. Other lines dont lose out from taking cs, so why is spellthief special.