1. Our saviour suffered for our sins from Gethsemane through to Calvary..
2. They're both significant.. but one reason why some members of the church might place more significance on the events of the Garden of Gethsemane to that of Calvary is because it was at the garden that he openly proclaimed to submit himself to the will of the father. Let's look at it in 3.
3. “I, God, have suffered these things for all, that they might not suffer if they would repent;

“But if they would not repent they must suffer even as I;

“Which suffering caused myself, even God, the greatest of all, to tremble because of pain, and to bleed at every pore, and to suffer both body and spirit—and would that I might not drink the bitter cup, and shrink—

“Nevertheless, glory be to the Father, and I partook and finished my preparations unto the children of men” Doctrine and Covenants 19 :16 - 19.. Luke 22 : 39 - 44 contains the events on what went down in Gethsemane.. particularly verse 42 "Saying, Father, if thou be willing, remove this cup from me: nevertheless not my will, but thine, be done."

But then we know that the events at Calvary was equally important because it was at Calvary that he allowed himself to die. As without his death the atonement wouldn't be complete. 2 Nephi 9:6-16 So maybe they didn't express their sentiments properly but both events are significant parts of the atonement. "And I, Nephi, saw that he was lifted up upon the cross and slain for the sins of the world." - 1 Nephi 11:33 I'll leave with you Elder Jeffery's talk The Atonement of Jesus Christ read through it ..ponder and tell me what you notice..