He has: the Royal Guard. I'm just saying that I doubt that the King himself as an individual person is strong.
And I've already told you that the Spirit King has no real power, outside being a symbol. It's mainly ceremonial.
Compare it to the pope: he has zero to none political power, but kill him and you will feel it. Same with the Spirit King.
can you supply evidence for continual stating the spirit king has no real power/ just being symbolic
only thing i ever remember being said about him was that he leaves SS to its own devices. perhaps thats where your thinking symbolic. hes symbolic in SS because hes an enigma as hes never appeared there.
as for his actual strength /power in terms of reiatsu it is obv unknown, but ask yourself this. If 0 squad is so powerfull, why would they follow him ? theyre in all likelyhood not saints trying to keep things ticking over...nor are they likely to be enamoured of his position of king. if its undeserved.
Id also point to the bit ages ago where bayakuya is talking about the 4 great houses having superior reiatsu and being able to achieve bankai because of it. If there nobility because of there spiritual strength then doesnt it logically follow that the royal family is even stronger
also the pope maynot have the power he once had. but he is far from powerless. go to the vatican and say that

its a country of its own with its own laws within italy. and the pope is at the top so he must have some authority xd
If he would be that strong, why would he need the strongest shinigami in the world to protect him? And if he would be that strong he would have a lot more power. In the end he's just some kind of puppet-figure with no power at all and is locked in his dimension.
same concept as why do captains have squads? why dont they just appear randomly and destroy everything that would have taken there underlings time and effort to beat...well because this is a manga and fights are boring if one side is overpowered...also realisticly they cant be everywhere at once so you deligate jobs to your underlings ...
as to why he needs them...well vasto lorde are (said to be) above captain lvl, and wait...squad 0 is uber strong....lets see ... I predict vasto lorde vs squad 0 at some point in the future xd