Pacing has to be watched daily. A budget spent by the twentieth leaves ten silent days, and one spent too slowly wastes the month entirely, so mid-month checks matter more than any end-of-month analysis.
Tracking fails quietly. A tag removed during a website update stops reporting conversions and nobody notices until a review meeting, so an alert when a signal simply stops is worth more than a dashboard nobody opens.
Percentage-based fees move every month. Invoicing them from memory produces awkward corrections, so calculating the fee from actual spend, per account, is basic hygiene rather than sophistication.
Reports arrive on the same days every month. Producing them by hand across twenty accounts consumes days that were sold as strategy, and a client cannot tell the difference between careful analysis and a late night.