[1] Float is subject to random fluctuations yet creates large revenue stream for banks or like agents.
Also causes may be summarized as deliberately, inefficiency, logistical situation and compensation related mechanisms.
[1] Countries can manipulate the worth of their currency by restricting or expanding the amount of float available to trade, and transfer agents of any kind effect a profit from holding this currency whether from a 12 hour or 5 day period.
The float time of funds can be used to defraud, by misusing it as a form of unauthorized credit, commonly known as cheque kiting.
As part of the Monetary Control Act of 1980 the Federal Reserve System charged banks for float, which improved check processing efficiency.
To reduce 'transportation float', banks have been able to scan their checks since the 1990s, and present them electronically at the Federal Reserve.