I'm currently shooting with an advance point and shoot (Panasonic LX100), I did ask myself if I should switch over to camcorder since camcorder tends to have better image stabilization and zoom range. But at the end of the day, the wallet is the deciding factor. Camcorder housing are generally more expensive than camera housing (Gate vs Nauticam), and there is virtually no resell value for camcorder and camcorder housing in general.
If you want to stick with camcorder, besides the AX100 (has poor white balance issue), the Panasonic HC-X1000 is the next option and there is housing for it. I don't think there is any housing for consumer camcorder anymore, so you end up have to buy $2000+ camcorder and $4000+ for the housing for the camcorder.
If you switch over to camera, the GH5 should be something to keep an eye on, even the Panasonic GX80 could be a good option since it has IBIS while shooting 4K video.