Most times where I've wanted a spanner was when dealing with battery terminals. The 3/8 inch is so deep on a Piranha, or similar tool, that one cannot use it and there's so much tool blocking the nut/bolt. I do have a Leatherman 1/2" by 3/8" MUT v1.0 Wrench but who carried a wrench with them all the time unless they are a mechanic?
That's the purpose of a multitool, multiple uses and multiple tools.
That one pen knife's version of the spanner would be great. Crunch is a vice-grip like tool, it applies pressure, and most often than not it flips apart when trying to use as a spanner. Now if I had the choice of a Crunch or a Spanner Wrench I'd carry the Spanner Wrench! On thing is no one makes a spanner that can open to 1 full inch. Instead most tend to stop at 1/2 to 3/8 inch.
Had hoped the Wenger S557 Wrench would of at least got to 3/8 on the end but it did not. I thought I edited the SAK Wiki page ages ago to put in a measurement guide. Petitioned the admins to add the wrench sizes to it, and gave reference on an MTO page. Haven't looked since to see if it got added.
• Universal Wrench: Smallest 5.5mm (7/32 in) to 7.9mm (5/16 in) Opening End