As far as I know pacifiers are just that. They are a security thing to pacify. :)
Both my boys had them. It was the first thing I put in my hospital bag! I got them off the bottle. Then when they went to bed they had a pan in the crib with a sippy cup of water and that is where the pacifier went. Not long after the bottle went I would tell them crib was only place for the pacifier. So if they wanted it they were put in the crib. I think that also was a nice safety zone.
Sounds like he is capable of reason. he knows that daycare doesnt allow it. He may just be stressed at the end of the day with other kids.
Maybe make a rule that he can have it on the drive home to settle in. If he needs (wants) it longer then when he arrives home he needs to climb on his bed or cuddle in the couch corner til he is ready to get up and be without. Or set a time limit.
Eventually he will feel more secure and need it less. Set up goals on a calender for when he will go from one stage to the next. like from time at home to only on the drive home, to only on certain days etc.
then make a date for it to be thrown out. I did this with my first and he had no trouble putting it in the trash on that day.
My second kept it for longer and after a few night of finding it still in the pan in the crib and not used i just took it out to see if he would notice and he never did.
Good luck and just remember - we all wish we could have some extra pacifing time after a hard day.