A properly sized and fitted phillabeg (half kilt or "small" kilt) with adjustable side waist straps does not--and should not--require a belt, and can be comfortably--and confidently--worn without a kilt belt, which, in turn, also means that it a sporran with a sporran belt can be worn with it with or without a kilt belt. I personally do not like the look of a phillabeg with an exposed top waist line without a kilt belt, but if the top waist line is covered--by either a sweater/jumper or vest/waistcoat--then the kilt belt can and/or should be omitted, and a sporran and sporran belt alone will, on most wearers, look quite trim, neat, flattering and smart.