It would be good if your team already has alot of early game pressure, taking smite on support does pressure the enemy jungler on its own if you play your part right, problem is you wont be as useful until you hit a phase of the game where both teams are purging objectives/hiding from eachother so you can get gold from an empty lane....
Its not that its bad, its just that the meta just doesnt favor late game champions and builds, you will be pretty far behind in gold from the other support but at the very least you can possibly help your lee sin/elise/shaco/nunu make the enemy jungler rage quit....you just wont have any pressure in lane without that lovely exhaust / support item sustain.