I used to tape all of my FB planes and the finish was great and the added weight was minimal, BUT!
After a while I noticed that there was a degree of separation of the foam/paper and the whole bird seemed to soften. My son had his stored in a somewhat damp shed and ALL of them are not able to be flown safely, (stored for almost a year). In the same shed he has a few painted birds and they are all exactly the way they were stored and all in perfect flying condition, (no warps, lifting paper, or other degradation).
Tape works and does add a little strength but it is not a long lived solution and can be extremely difficult to make a repair where the repair is not extremely visible. If you use tape all is good except the lifespan of the model whereas painting done properly can give very long lived models, (crashes and hangar rash excluded).
I personally love the extra rigidity that the paint imparts for so little added weight!
Try both for yourself!
Have fun!