The simple answer is that there is a huge difference between these two observances. One is a biblically sanctioned festival of God; the other is a man-made festival without biblical authorization. One teaches us how to live godly lives; the other masks this important truth.
The Days of Unleavened Bread, commanded by God (Leviticus 23:6) and observed by the early Christians (1 Corinthians 5:6-8), teach us to put sin (represented by leavened items such as bread and cake) out of our lives. This festival teaches us that we must overcome sin with the help of God's Spirit and live righteously.
Easter, in contrast to the Days of Unleavened Bread, not only lacks biblical authorization but was instituted by men who deliberately replaced God's commanded festival with one derived from paganism to make Christianity more accommodating to converts who wanted to hold on to pagan traditions. In doing so, they imposed on this festival a Christian meaning—to celebrate Christ's resurrection.
As wonderful as Christ's resurrection is, the Bible specifically tells us to annually commemorate His death, which we do in the annual Passover observance (Luke 22:19; 1 Corinthians 11:24-25), but it does not give the same instruction about His resurrection. We do essentially commemorate Jesus' resurrection, though, in the commanded festival of God during which it happened—the Days of Unleavened Bread. His resurrection is crucial to the plan of God and the process of leading us out of sin. Indeed, we must progress beyond the fact that Jesus was raised to following our living Lord in the way we live our lives.
By the way, where do you read about using rabbits and Easter eggs to remember Christ's resurrection in the Bible? Answer: Nowhere.
Given the history of Easter, it is quite understandable why so many people today think of Christianity as only a celebration of what Christ has done for us instead of the honorable quest to live godly lives. If you want all the facts, read our free Bible Study aid booklet Holidays or Holy Days: Does It Matter Which Days We Observe?