Wearing clothes is a very common activities. We believe there is no great technology involved in clothes, but reality is that we consider this field so ordinary, not because the degree of scientific knowledge used in this field is limited, but because we have become so familiar with this product. In reality textiles and clothing were one of the earliest fields to use scientific knowledge, and because of the long history of it development, textile industry has contributed substantially to develop many other fields of science and technology.
A huge positive impact was that Europeans were exposed to goods they weren't really aware of before - spices, luxury textiles and so on. This caused massive amounts of trade with the east, and had a huge impact on the development of the economy, and cities associated with the trade grew massively. Many merchants grew hugely rich, and because kings relied on loans from these merchants, barriers to travel and trade within Europe were reduced. The flow of ideas of the Renaissance would not have happened without this shift.
Another positive impact is that it was the beginning of the end of feudalism.
Another positive impact is that the Classical knowledge that had been preserved in the east and forgotten by the west was going to be rediscovered as a result of the renewed contact between east and west.
Another positive impact, if you really want to be cynical, relates to the over-population in Europe at the time. There was a lot of violent feuding and squabbling happening in Europe because of an over-abundance of younger sons of lords. This was greatly reduced because Pope Urban gave them an opportunity to get themselves killed elsewhere.
Obviously there were also negative effects, mainly having to do with the vicious slaughter of innocent civilians, and centuries of hostility and distrust established afterwards.