This value (roughly said) defines the time-span that it may take to completely open a TCP connection. This is started by a SYN packet, and if the SYN-ACK packet doesn't arrive during the time you can configure here, the "half-open" connection is dropped.
Then main reason to keep this short is that this is one way to run a denial-of-service attack: If your system is waiting 1 minute if some (every) half-open connection will finally become a fully-established connection, it has to keep a rather long table of connections. By just starting to open enough "half-open" TCP connections you can block a system so that it cannot accept legitimate new TCP connections anymore.
So having this value on a unnecesarry high value is kind of dangerous. And 1 minute is too high in my opinion. 5 seconds should be enough to establish a TCP connection - remember: that is not, that everything has to be over in 5 seconds - just that the connection has to be completely established in max. 5 seconds.