Distribution-type graphs (histogram/kde) with weighted data

You have to understand that seaborn uses the very matplotlib plotting functions that also pandas uses.

As the documentation states, sns.distplot does not accept a weights argument, however it does take a hist_kws argument, which will be sent to the underlying call to plt.hist. Thus, this should do what you want:

sns.distplot(df.x, bins=4, hist_kws={'weights':df.wt.values})