Anyone who has tried to construct equipment using SMDs (surface mount devices) will know the difficulties and frustrations experienced in handling these tiny components. If you attempt to pick up the device with tweezers, it will often squirt out of the jaws travelling at high speed, never to be seen again!  If you do manage to manoeuvre the pesky little thing into position, the chances are that as you apply solder to the first pad, surface tension in the pool of molten solder, will cause the chip capacitor, or resister to stand up on its end like a miniature tombstone. To prevent this amusing little antic, the device needs to be pinned down during the soldering process.