Advantage of TCP in regards to UDP

Question

Back in the day when I played StarCraft on battlenet and locally I would select how I would connect to other players. For local I used UDP, listening to the videos now I can see why I used UDP. It is apparently faster than TCP though lacks guarantees. Clearly it worked without the guarantee so I wonder what the danger of UDP is?

so for clarity my question is, "What is the danger of sending a packet without a guaruntee? If the danger is tolerable why is the slower TCP used? What are examples of UDP failures in gaming or other packet use?"

Thanks for your input.

Answer 1

Presumably your local network was fairly reliable, and few packets would actually get dropped. When sending packets long distances across the internet, the chances of a packet getting lost are higher.

(Also, in a game, if the packets are saying "Unit A is at location (x,y)", then if you miss one packet, the next packet may provide the new (x,y) location, so a couple of dropped packets might be acceptable. The consequences of dropping packets during a financial transaction would be more serious...)