Having had 2 data cards stolen from GPS units in our club's aircraft, as CFI I resolved not to waste any more money on buying new ones. But these weren't moving map GPS units (GPS 150 and GNC 250), so provided that the correct lat/long or aerodrome names had been entered in the route, the display showed DTK, TRK, GS and ETA - with the CDI bar showing cross-track error. Perfectly adequate for PPL flying, in my view.
Airspace avoidance was achieved by pre-flight planning on a current chart.
But a moving map unit, if it displays airspace, really should be kept up-to-date. Particularly in the impatient 'get in and go' current way many people fly these days.