To get there faster, you simply select a lower speed (CLB or OPEN CLB). Indeed Airbus clearly states that use of VS mode is not recommended since it can confuse the FMGS (selecting an unattainable IAS for a given VS can confuse the FMGS).
The only arguments I can think of are to use VS to avoid large pitch changes.
VS can be useful on the A320 series when you are heavy, the wind is unstable, and you are above FL300. In these conditions the aircraft VS can rapidly oscillate between (for example) 300fpm to 1500fpm in order to maintain the selected IAS as the wind changes. Small changes in IAS trend = large change in pitch/vertical speed under these conditons. This can be avoided by selecting M0.80 (ie power on), VS+1000, and closely monitoring your IAS as it varies.
There is also an argument to use VS during a very turbulent descent. OPEN DES can again cause large rapid pitch changes, and DES can cause VS-1000 and power to be added if you temporarily go below the profile (you probably want to get under the profile/wx in these conditions). So if you wind the speed back to green dot and select VS-2500 (for example... depends on altitude etc), you should keep the power off and a fairly constant descent rate even as the wind changes. Again, you must monitor IAS closely.