It does depend on the home and the condition of the saltillo, but in general I would say “Yes, It can hurt home resale.
Saltillo tile is a soft tile, it is porous and needs to be stripped and sealed often. This makes it “High Maintenance”.
It is often found in a southwestern Territorial and Santa Fe style homes. It is also found in other styles but not by design, usually it is a preference of the owner.
If it is in one of the three mentioned above it is expected as part of the style of home and those purchasing this type of home will generally accept the Saltillo as part of the design. There are new ceramic tiles which look almost identical to saltillo maintaining the design style without the high degree of maintenance required by traditional soft saltillo tile.
Therefore, it is up to the owner or buyer to decide about purchasing a home or selling a home with saltillo tile. As a general rule of thumb I would say again Yes, it can hurt home resale because a lot of people don’t want a high maintenance floor.