battery power: DC converters Enable pin vs. switch

I am developing some electronics (about 200mA draw) which are powered by 2 AA batteries in series using a MCP1640 converter for having clean 3.3v. Just like many of its colleagues, the MCP has an enable pin that - when pulled to ground - disables power output and consumes about 1 uA.

Google couldn't tell me why using the enable pin and wasting the small but existent 1 uA is better than a simple switch that cuts of the + or - directly after the battery.

Can anyone enlighten me please? What is the best way of implementing an on/off switch for a battery-enabled device?

If you can fit a switch, there is no reason not to. But there are a lot of situations where a circuit would drive the pin, like disabling subsystems during sleep of an MCU or soft on-off with multiple switchon mechanisms.

Manual switches are very restrictive, but if your project is suitable for manual manipulation, by all means. 0 is less than 1 any way you slice it.