Is box plot an easiest way to detect anomalies making use of the popular way Q1 - 1.5 x IQR for lower bound and Q3 1.5 x IQR for upper bound?

How often this 1.5 multiple changed by the statisticians. I mean are there use cases in which some other multiplier will give a better result of detecting outliers?

Practically is this technique used specifically to detect outliers only? For instance to scrutiny banking transactions by individuals earning yearly between 50000−75000−75000 that surpasses of others on the upper side, finding its place beyond Q3 whisker. Falling as outlier on the lower side (Q1 whisker) might not be a reason to scrutiny as entire income can be saved.