Bantams are very pretty and the eggs are lovely, with a larger proportion of yolk to white than eggs from full-sized hens. However, many bantam breeds are a real pain when they constantly go broody and spend all their time in the nestbox. You then have to remove them and isolate them in the light and open air until their hormones cool down and change back to normal. If you don't do this, they will sit and sit, without bothering to eat or drink enough, and will lose condition by going on longer than the 21 days it takes for a normal hatch. And of course, you won't even get any little eggs whilst all this is going on. Not much fun, if you want active and productive pets! Silkies are the worst, but not the only offenders. Before electric incubators were invented, farmers and gamekeepers used Silkies to hatch out clutches of chicken and pheasant eggs for them, as they were such determined sitters. Many bantams are very lively, good fliers that like to roost in trees in the neighbour's garden given the chance, and can be quite feisty as well.
Some bantams will become very tame, but if you want hens as pets, you may be better suited for a start with some of the larger hybrids that are bred to be calm and friendly in order to live peacefully in crowded conditions in commercial units. And you then get a good daily supply of really excellent eggs, and why not? - children love collecting them and you can really taste the difference. Hybrids come in all sorts of colours, all beautiful, they are bred not to go broody, and if you avoid the flighty Leghorns (sold as White Stars) you can soon tame them. They will probably be less expensive than bantams because they're bred commercially in large numbers, and a good choice is usually available locally. Specialist birds which are bred by small independent producers will usually cost more, and this may be worth it to you if you really want a particular type and know the breeder by reputation, but they probably won't be vaccinated against common diseases like the hybrids will be, and may come from small flocks where inbreeding is a problem, and there may also be incurable residual infections within the flock such as Mareks disease or various bronchial conditions which unfortunately are very common in home-bred birds.