You can try it out with your Dataset, having different Columns with values having different Ranges.
Scaling using StandardScaler helps in standarization of data, since then calculations for several Distance-Based Algos is better.
Z-Score always converts our particular column into Scaled Data having Mean = 0 and Standard Deviation = 1.
from sklearn.preprocessing import StandardScaler
scaler = StandardScaler()
model = scaler.fit(X_train)
y_test = model.predict(X_test)
Note: Here, I am not applying StandardScaler on y_train, and we shouldn't apply StandardScaler on y data.