I caught the tail end of an interview with an admiral on the news the other day, he asserted that Iran, in spite of its proxy warmongering stance in this growing escalation, really don't want an out and out war, simply because that could result in their regime being swept away. Iran, unlike us here in the west have an overwhelming young population who just want to enjoy the freedoms of their western counterparts, and as such, I would imagine would love to sweep away this evil theocracy that thwart their liberty.
As others have already pointed out access to the Suez canal is vital for shipping goods, the route around Africa and the Cape would take ages and have far reaching consequences as far as shortages and prices. The recent container ship that somehow got stuck in the §uez canal certainly affected businesses and consumers in that respect.
Whilst I don't think the West can sit back and let this situation continue, I wish it wasn't always Britain who goes in with firepower as if we are some sort of super power equal, when clearly we aren't.