http://mens-fashion.lovetoknow.com/Dress_Code_for_Smart_Casual said:A smart casual dress code is one that is more relaxed and open for personal expression. This dress code can be found in workplaces where employees need to look professional but are not required to wear suits. Smart casual looks can also be worn to events, on dates and whenever you feel the need to impress. From dress pants to jeans, there are many possiblities for you to explore in this type of apparel.
Guy first guy with just the short sleeve shirt and jeans is probably pushing it, but:
This form of dress is much more suitable than a suit in a range of social situations, including many interviews. Part of dressing for an interview is dressing appropriately for the environment you will be working in. You want to show you can fit into their workplace culture. True, a suit will likely not lose you points, but it certainly won't help in many situations. I did myself no favours when by showing up to my TV work experience in a full suit and had to quickly learn to adjust my dressing style quickly.