"I read several paragraphs, and didn't see what the Use of Sarum was, what the benefits was, or what problem it would help."
When attempts to restore Sarum (pre-Reformation English rite) were made, it was generally the 19th century and the general mood was Romanticism and nostalgia for the medieval era.
I frankly see little point today of restoring Sarum, because first of all you need a minimum of "culture" around it, and it just won't wash with modernity or post-modernity, even among "fogeys". A good question to ask is whether our nostalgics of today would be prepared to go back to medieval penitential discipline and general conditions of life in the 15th century (fanatical inquisitors and all).
You also need the liturgical books and clergy who know the ceremonies. Everything is well documented, and "reconstructions" have been performed in various churches in England and Scotland. It has historical and aesthetic value.
What about the liturgy of the future in an Anglican context, or that of a part of Anglicanism in communion with Rome. I think the Anglican Use is on the right track, but it needs revision to remove the influence of the Novus Ordo - for example the Offertory prayers. The Sarum or Dominican prayers could go in the place of the Novus Ordo formulas. The three-year lectionary is a positive development and is widely used in the TAC to which I belong.
I have always felt that the Tridentine Rite is not really the thing for an Anglican context, and in the Roman Church it did need reform. The problem is that it didn't get the right kind of reform. The subject is too vast to expound upon here.
The real issue is that Christianity is in a critical situation. There are Christians who need to continue to sustain their faith with traditional liturgies. The Church also has the job of evangelising, and liturgies have little role to play there - not with the kind of people who haven't discounted belief in Christ, but who would never set foot in a church.
We have this vocation if all Catholic and Orthodox Christianity is not to go the way of Sarum.
Fr. Anthony Chadwick