Iran's friends in Yemen would make Iran stronger if the Houthi win the war there:
The Shia rebels are again threatening commercial shipping entering or leaving the Red Sea. The latest tactic appears to involve putting several heavily armed rebel fighters on one of the many local cargo or fishing boats that operate along the coast and then have the Shia fighters fire RPGs at seagoing tankers or cargo ships. In late 2015 government forces regained control the Bab Al Mandab strait, in the Gulf of Aden, between Yemen and Djibouti and astride the shipping lanes leading to the Red Sea. This included the peninsula that extends into the Bab Al Mandab strait. This made it easier to monitor ships coming through, especially those that might be carrying Iran arms shipments. More important to the Arabs (and Egypt) was the fact that rebel control of the Bab Al Mandab strait was a potential threat to Suez Canal traffic. The canal fees are a major source of income for the Egyptian government. Saudi Arabia also exports oil and imports many other goods via that narrow (40 kilometers max) strait. Government forces also seized control of Perim Island, which is in middle of the straits and normally contains a coast guard base. The small Shia garrison fought to the death in a battle that lasted a few hours.
Because Iran has the ability to exert pressure in the Strait of Hormuz to throttle oil exports from the Gulf, the Saudis made alternate oil export routes to the Red Sea.
I've long noted this opportunity for Iranian pressure on that alternative route.
And keep in mind that Iran's influence in Syria, Lebanon (through Hezbollah), and Gaza opens up opportunities to interdict the Suez Canal at the northern end of the Red Sea and to hamper any oil exports from the eastern shore of the Mediterranean Sea.
