I agree for the low skill weapon but, can you give me some references about the "no accuracy" part ?
Because tbh, mine tell me exactly the opposite...
Well it took training but not the years and years for the bows and long bows. As far as accuracy I believe the bows were more of a mass fire weapon than the cross bows.
While it is true the crossbow was a common weapon for less skilled soldiers and militiamen throughout the Middle Ages and the Renaissance, their merits as a ranged weapon were far from being simple inaccurate mass-fire weapons. First and foremost, we should use the general historical context of cRPG as a basis for discussion, which in of itself spans a wide berth of time, featuring armaments from around the 800s to the 15th or 16th century, which is almost a thousand years of military stratagems and technological development. However, the bulk of the weapons we have and the general context intended for the original M&B Warband is around the 13th to 14th century.
Before I do a more nuanced contrast of the abilities of a stereotypical medieval longbow & crossbow, the principal difference between the two is loading time. Compared to a crossbow, which takes about 10-20 seconds to load and then loose a bolt, a longbow can do so 2 to 5 times as fast, depending on the make of the bow, abilities of the bowman and where his target is. However, almost all other aspects of either weapon around this time period were relatively similar; longbows and crossbows had an effective range of approximately 250-350 yards, along with a similar projectile speed (approx. 137 fps) and a similar ability to penetrate plated targets (with the crossbow performing better at close range and the longbow performing better at long range). However, while the longbow was relatively unchanged in terms of its capabilities throughout the 13th-14th century, crossbows would grow to outperform the longbow in the latter portion of the century and continue to improve throughout the 15th century (with both being phased out by firelocks and gunpowder weapons by the early 16th century).
In terms of skill required for usage, longbows necessitated skilled bowmen, usually trained from birth, to be properly and effectively wielded (much like mounted knights with their steeds and lances). In contrast, crossbowmen needed much less training, but still required a good understanding of the functions and performance of their weapon to use it well. As a result of the difference in skill necessary for each weapon, crossbows were much more popular around Europe due to the comparatively much lower cost of training and fielding men to use them, whereas longbowmen required exorbitant amounts of time and money. Additionally, considering the feudal context of that period in history, crossbowmen could be much more reliably fielded in armies, as burghers or rich serfs could easily pay for their own equipment and training when the need came, whereas longbowmen could only be pooled from a small population dedicated to that position.
TL;DR - Crossbows and longbows performed relatively similarly on the medieval battlefield, with crossbows being much more easy to use and as a result were much more popular (and cheaper) than the longbow.