I think that's a bad comparison. Intuitively this might feel less healthy because you are consuming more than twice as many calories with the butter. Double check your intuition on this one. People on high fat diets tend to eat less volume as compared to those on high carb diets for a good reason. Fat is more than twice as calorie dense as compared to sugar.

1 cup of sugar = 201 g. 1 cup of Butter = 227 grams. 201/227 = a given volume of sugar is about 89% as heavy as the same volume of butter.

1 gram of sugar contains 4 calories. 1 gram of butter is about 7.2 calories (a gram of fat is 9 calories and butter is roughly 85% fat + milk solids and water). 4/7.2 = a gram of sugar contains about 56% as many calories as a gram of butter.

4 tbps of sugar = 50 grams = 200 calories

4 tbps of butter = 56.8 grams = 408 calories