I transitioned from guitar to bass and relied on a pick for the first couple years. A bass player friend convinced me that all I had to do was put the pick down and get to work. It took a couple months, but it became very natural to play without one. I think it is physically easier to play without one. Using a pick tends to involve your whole forearm up to the elbow. The tendon on the back of my right elbow was substantially larger than the left when I was using a pick. Playing with your fingers moves most of all that motion just into your hand. I feel more connected to the bass not using a pick, too.
I would start off NOT using a pick, get proficient without one, then work on using a pick for the songs you feel need one.
I would start off NOT using a pick, get proficient without one, then work on using a pick for the songs you feel need one.