As to pros and Cons...
1: Any battery operated device will have a up time. But these are Quick to charge.
2: If you use the Headphones - then the standard ones have small ear pads. I like; SOME do not. ( Not so good on a windy beach)
3: Have their own true volume control - as battery powered. I never had a problem with volume or clarity. EVERY ONE HAS different hearing
4: Transmitter is light and reasonable robust.
5: Not submersible
6: Standard Headphones are light weight
7: I never found LAG when swinging and pin pointing.. Then again if you swing like some, I doubt any sound system will be able to keep track.
8: I never had Interference... Used inside on the TV and have BT and Wireless in the house
But I have to assume that if you stick a PI unit and or some Phones or some other transmitting device in super close proximity... That they could always be a chance... But I have not had and one of teh Guys in NZ said he had no issues around parks with MASIVE Lighting systems and Transformers and cell towers etc.. ( Then again - it was NZ LOL)
If you get the Transmitter and the Receiver and then use your own headphones. Then many performance issue etc will come back to the Headphones you use.