I don't claim to be an expert in regards to the below. It has just been what I have noticed in my years of tinkering with a lot of 1911s, springs, and buffs...
I believe they do serve a reasonable purpose. Probably more so if you have an aluminum framed gun, shoot hotter +P or Super ammo, 10mm with full pot loads, or put a lot of rounds down range on one platform. Some claim a reduction in recoil sharpness, but let's not discuss that here. Let's also keep in mind most people will never shoot more than a 50-round box of ammo a year (which is why Hi-Points and Kel-Tecs still sell LOL).
What you certainly do when adding a buffer is shorten the slide's rearward/forward "runway."
With these add-on buffers the slide's maximum rearward length of travel is reduced, and forward travel is shortened (subsequently your slide has less inertia to strip the next cartridge). If the 1911 was full auto, that buffer would also increase it's rounds per minute. This can also potentially compromise a magazine's ability to push the next round up in time, especially with older mags and cause other potential reliability issues. To help explain this, think of why some people conceptually prefer the slingshot method of reloading over slide stop (not to start that debate).
I believe this issue can be exacerbated with a buffer when you go from a 5-inch barrel to a 4.25, on down the line.
For myself--personally--I would use the buffer at the range and remove it at the end of the session if I planned on carrying it. I know many people have never had a problem/others did, etc. but this is my opinion. You can consider it cheap peace of mind with no fear of it failing you when you need it that way.
I would also change the buffer at 1,000 rounds and add a fresh recoil spring (springs are cheap).
YMMV.