Depends on the premium, cover and terms/condition of the gadget Insurance. With claims under your Home Insurance, you have to consider the excess and future increases in premiums. So if a gadget policy premium, cover and t&c's are such that it makes it a better way to Insure items, then that is a choice you may wish to make.
Some gadget policies do appear to offer cover that Home Insurance don't provide. For example Protectyourbubble can also provide cover for breakdown of an item. Home Insurances do not cover breakdown.
What I would suggest that you do, is write down a list of the situations (risks) that you want to be covered for and then start comparing the products available, weighing up the premiums for each to decide which is the one that suits you best.
Make sure that the comparsions you make are on the same basis. e.g Does the policy cover new for old replacement if the items is stolen or damaged beyond economic repair. What would the Insurers do, if the exact make/model is not available as a replacement.