Sliding doors can open out a dining room to a living room, and it gives you the opportunity to have a more open plan living space when it suits you, especially if the opening is quite large. Sliding doors are also regularly used in bedrooms to open out to dressing areas, as well as in conservatories and kitchens, and there are plenty of styles to choose between.
The operation can be different too, and so too can the materials used. A solid oak door can look really nice in a modern lounge area, while glass sliding doors are always beneficial if the space opens out to the garden or conservatory, as you can get nice views of the garden and plenty of fresh light.
If you have the opening to facilitate a large sliding door then it can add a unique style to your property, whilst making it feel lighter, airier and more open when it suits you.