I agree with sm to a point.
I see no harm in getting another Rem Choke barrel to play with, and to use for other applications where IC might not be the best choice.
I would keep the original barrel totally original. It can always be put back on the gun, and will almost certainly outperform the Rem Choke barrel with an IC choke.
A shotgun is to enjoy and the more utility you can get out of it, the better.
On the other hand, you could add $50.00 to the cost of the 1100 barrel and buy yourself an 870 Express with Rem Choke barrel for those other occasions where you might want something else.
For me a lot of the fun of the shotgun is not only in the shooting, but also in working on them, testing various changes and tweaks, and thoroughly understanding exactly how they work.
The 1100 is an excellent moderately priced shotgun that will last indefinitely. There have been millions made, and they are still being made, so they are not going to appreciate in value in our lifetimes. It is a perfect candidate for "tinkering".
Everybody needs at least one more shotgun.