I typically carry a polymer framed gun.
For home defense, in competition or for fun at the range, the weight savings is pointless. Might as well have the extra weight in those situations.
To expand on the unsaid part of what JohnKSa said, both have their advantages.
Polymer (and alloy) are best in a carry gun where the weight savings is most meaningful. A polymer pistol lets you carry a larger gun with less weight (or the smallest and lightest possible options), which is more comfortable
when carrying and can lead to you being less likely to leave it at home.
The extra weight of a metal gun (especially steel) is an
advantage in the applications he mentioned. You don't need the lighter weight for carry or in a range gun. The extra weight means it is more comfortable to shoot, which equals more rounds at the range which means you will get better faster. Being more familiar and accurate with a gun (due to more practice time) means you are better prepared if you ever need to use it. In the moment, the extra weight means less felt recoil, and less muzzle flip. This means you will be quicker getting back on target, and thus, you will have faster follow up shots. At the range, a gun you can shoot more comfortably and more often is generally more fun. For home defense or competition, a gun that can be more easily and more fully controlled, and that has faster follow up shots, can make a huge difference in your effectiveness.
I get it, I like polymer too (I didn't use to). While I love a wood and metal revolver or 1911, and CZ 75 based CZs and classic P-series SIGs are among my favorite guns, I probably have more polymer guns at this time. When I carry, it is mostly polymer or alloy (certainly they are metal, but quite a bit lighter than steel). However, I love having more choices, and there is no doubt that metal (and especially steel) guns are better for some applications.