The bottom line is that essentially there were no medals available to recognize troops' gallantry during the Civil War other than the Medal of Honor, and the criteria for its award during the Civil War were very loose. The Certificate of Merit, awarded during the Mexican-American War, was essentially moribund, and there was a desire for a new battlefield decoration for valor. A proposal for such an award was submitted in the Fall of 1861, but was opposed by General Winfield Scott, the Army's Chief. After Scott's retirement, Congress and the Navy developed a medal to honor distinguished Naval service, which was signed into law in December 1861. In February 1862, Senator Wilson posed a resolution to establish an Army Medal of Honor, which became law in July 1862. This law provided for awarding a medal of honor "to such non-commissioned officers and privates as shall most distinguish themselves by their gallantry in action and other soldier-like qualities during the present insurrection." In March 1863, eligibility was extended to officers as well as enlisted men. As can be seen from the foregoing, The MOH was essentially the only medal available to recognize troops, and it was subject to very loose requirements (remember the "gallantry in action and other soldier-like qualities"?). Thus, many were awarded during the Civil War for reasons which today would be considered not worthy of the award. As the military developed its awards policy after the civil war, more medals with differing requirements for qualification were made available, and the requirements for the medal of honor were gradually raised to today's requirements of "distinguish himself conspicuously by gallantry and intrepidity at the risk of his life above and beyond the call of duty", and also required that the act of valor be performed "in action involving actual conflict with an armed enemy". In February 1917, an Army Medal of Honor Review Board rescinded 911 (mostly Civil War) medals from the rolls, noting that they were not deserved, even by the lax standards of the civil war, such as those given for reenlisting or for serving as members of Lincoln's funeral escort. Thus, basically the answer is two-fold: the original MOH was the only decoration available during the Civil War, and the criteria for its award were very loose. Since WW2, there is a plethora of awards available to recognize soldiers who perform well, but do not meet the strengthened criteria for the MOH, so the MOH is granted very rarely.