D
Darkwood
These PIR sensors are for internal areas not exterior, normally in toilets and other infrequently used areas such as large/small storage rooms etc. Most internal type fittings, either being surface or recessed, are still generally based around fluorescent and CFL lamps of one description or another, unless were talking about small LED downlights, so it's hardly bad design, no-one is going to fit incandescent lamps these days are they... lol!!
My bad i was explaining for external PIR units ... if its in a cupboard that's rarely accessed then fine its no worse than using a light switch it becomes as you know problematic when traffic in the area is higher and it end up switch on/off all day Ive seen many systems ripped out of through-fares in schools as lamp-life plummeted and got costly but yes agree PIR are fine if you would generally be switching the lights on and off at the same count.
PS Whos said these are indoor kits... I can't see where the OP has said what they are only mention of indoor was brought up by yourself?