This won't really extend your brass life, 38 spl brass lasts practically forever anyway with target loads. However, it might increase your accuracy a tad. You do not need a heavy roll crimp with light 38 loads, light roll or "taper" is fine.

For your heavy loads, stick to a medium to heavy roll crimp, especially if they will be used for anything serious like self defense. 38 isn't a powerhouse of recoil and bullet jump, but still it's best not to take a chance.