This has not been my experience. I commute in all weather and my bike with entry level Tektro disc brakes stops substantially better in wet weather than my bike with rim brakes.
Bringing weight into the discussion indicates you are one of those bike riders who should probably just be ignored.
Well, anyone riding uphill will appreciate losing weight.
The selling point of disk brakes though, is first and foremost the ability to modulate the braking effect, even in adverse conditions. That's why some road gruppos now come with hydraulic rim and hydraulic disk options.
Especially the lack of initial bite in wet conditions on a rim brake can be worrying, when there is a lot of sludge on the rim - washed up road dust that coats the rims and reduces braking efficiency over that of just water and a clean rim. If my health allows me to still ride in two or three years, I will most likely eye road-bikes with disk brakes, and consider them. I might still reject them over the atrocious maintenance procedure and the danger of slow hydraulic leaks, but when they work they're great. It will probably also depend on where I will live. If I still live in the mountains, having something that gives me more confidence in the brakes in wet descents is well appreciated.
Of course, none of this has any impact with regard to OP who literally just needs a bike that has working brakes. In town, any set of reasonably well maintained brakes will get a bike doing reasonable speeds to stop where it needs to stop. People even ride bikes without brakes in town, after all. (I call those "idiots".)
OP needs a city bike with a nice basket for his gym shoes and towel, and not any kind of sporting vehicle.
Repeat after me: OP seeks transport, not exercise!