Is the '之' in '要之何用' also regarded as a possessive article?
之 following a noun is a possessive marker
之 following a verb  '要'(have) here is a pronoun for 'it'

More examples of 之 as a pronoun when it follows a verb:

叫他进来然后杀(之) - ask him to come in and then kill (him)

没有酒就以水代(之) - If there's no wine, use water to substitute (it)



要(钱)何用? = having (money) for what use?
要(之)何用? = having (it) for what use?
'之' is the pronoun for 'money'