One of the greatest levels of complication in our emails is supporting a set of rules to display the donor's past donation amount. Because we always have edgecases where a donor might have given in a non-native currency (say, ILS in enUS), every email has rules to display every currency symbol we support.
This is done by nesting multiple rulesets within one another to tell Silverpop a) the right symbol to display based on the currency code and b) where to put the currency symbol (right or left of the amount). If the currency symbol was already present in Silverpop, we could get rid of 1 layer of sophistication, making my live a lot easier, and making us less reliant on Silverpop specifically for its dynamic content tools.