1) Bulbs let renters have adjustable lights without having to rewire a house they don't own. That's 1/3rd of the market. 2) Replacing one bulb every few years

1) Bulbs let renters have adjustable lights without having to rewire a house they don't own. That's 1/3rd of the market. 2) Replacing one bulb every few years is much less time/money than a wiring project IMO.