Young Brunette Girl With A Crossbow Weapon

Crossbows have a much smaller draw length than bows. This means that for the same energy to be imparted to the arrow (or bolt) the crossbow has to have a much higher draw weight. A direct comparison between a fast hand-drawn replica crossbow and a longbow show a 6:10 rate of fire. Or a 4:9 rate within 30 seconds and comparable weapons.
Legal issues
Can. 29 of the Second Lateran Council under Pope Innocent II in 1139 may have banned the use of crossbows against Christians. The authenticity, interpretation and translation of this source is contested. Military historian K.C. Eyre suggested in an unpublished paper that the more probable explanation was a ban on William Tell-like marksmanship demonstrations, in which people would shoot apples off heads, and so on. Given the high-risk nature of this sport, it is easy to see why the Church might discourage it. Given the generally nasty nature of conflict at the time, and the proliferation of ballistic, blunt and edged weapons in use, it is harder to see why the Church would have singled out the crossbow in particular as unsuitable.