Scale length can make a real difference in the way that a banjo plays, feels, and responds. Scale length is the active length of the string. That is the length of the string from the nut to the bridge saddle. If we have two strings of the same diameter but they differ in length and we wish to tune them both to the same note, less tension will be required to get the shorter string up to pitch. Why is this so? The longer string, because of its added length is also heavier and requires more tension to bring it up to pitch. A banjo with a longer scale length generally has strings that feel tighter and may be more difficult to push down against the frets.
A string that is under greater tension has a snappier, quicker response, and depending on the banjo, more volume too. So, a banjo with a longer scale length and greater tension often does translate to a banjo that sounds a little more responsive and punchy. A short scale banjo may lack some of the snap that I like for really laying down the rhythm in a band. Some of that snap may be added to the short scale banjo by using a heavier gauge string.
Every banjo has a unique sound. It takes some experimentation to find the “right” string for a specific instrument. The string gauge will have a notable impact on the sound and playability of the banjo. A heavy gauge string will have greater tension than a lighter gauge string tuned to the same pitch. Heavier gauge strings are usually a bit louder than lighter gauge strings but are harder to push down with the fretting hand. The trade off between playability and volume is sometimes worth it. Indeed, sometimes a lighter gauge string will produce a more pleasing tone in spite of having less volume.
Experimentation is encouraged to find the string that suits your own needs the best. However, bear in mind that when switching around string gauge you will be changing the physical demands that are placed on the instrument. This can have consequences that are not always easy to predict and are not always pleasant. Switching to a heavier string can result in higher action, buzzing, and possibly the need for adjustments to bridge height and head tension. Switching to a lighter gauge string may also require adjustments to reach maximum playability. If you have a new banjo, the maker may recommend a certain string gauge.