To be honest, in terms of self-defence training, you'd be better off wearing footwear anyway, as that more accurately replicates the situation you would need to use your techniques in. Many specific self-defence styles, such as combatives, wear footwear while training. It's quite a different experience throwing techniques in different types of clothing such as shorts/trousers, vest/jacket so if you get the opportunity to try them out, go for it!