Costs of using ant as a scripting language?

[Nicholas Christopher]

I've use ANT now very happily for build, test and deploy of a Java app across
windows and linux. Usually my stuff deploys both a shell script and batch file
for launching the app. What I wonder is why shouldn't I just launch the app from
an ant task?  Let ANT worry about the script & batch issue. I know that it's
completely viable (I do it for testing) but I'm just wondering what the
overhead/cost is of launching an app from ANT vs a script?  Any thoughts?