The difference between fractional reserve maturity mismatching and other forms of maturity mismatching is that via fractional reserve banking the money supply is increased.
Another difference between fractional reserve banking mismatching and other mismatching is its legal and ethical status.
Fractional Reserve Banking as a Promoter of Excessive Maturity Mismatching
Fractional reserve banking boosts the use of maturity mismatching by increasing overall liquidity and financing opportunities.
Central Banking as a Promoter of Maturity Mismatching
If the central bank accepts those long term assets as collateral against new loans, the risk of maturity mismatching is reduced.
Effectively the central bank removes the limits to maturity mismatching in general and credit expansion in particular that exist in a free banking system.
When there are malinvestments committed due to maturity mismatching this cannot be made undone by bailing out banks.
Government Guarantees as a Promoter of Maturity Mismatching
Thus, government guarantees help to remove the limits to maturity mismatching that exist in a free banking system.
Moreover, by cartelizing the industry and bailing out failing banks, the guarantees together with fractional reserve banking and central banking remove the limits to maturity mismatching that were set by competition on the free market via runs on short-term assets and short-selling.