A large majority of tile sets that can be used in Tiled consist of tiles that are not square. While we can break some tiles into smaller sets, this doesn't alway work well with positioning when tiles are odd shapes. One map 'pond' for example in Tiled is 1 tile. For construct this might be made into 7 tiles.
Using sourced images are a nightmare for using in construct.
The alternative is to support the Tiled maps where you don't use an image sheet. The end benefit is the same.
Considerable time can be saved for Tiled users.
Time can be saved in design if a sprite can be defined as a single item not multiples.