I'm not convinced by the sheet music argument. You can't go wrong by developing a skill, but I think it's entirely possible to become pretty awesome without reading sheet music. It's only useful if you're actually learniong music by reading sheet music.
When you're starting out, guitar can be learned from teachers, or through transcribed music on tablature or sheet music. For classical guitar it's probably a must because most such music will be written on sheet music and be available as such in shops.
But if you want to learn more modern music, you will rely on the skill of your teacher, or the person who wrote out the sheet music / tablature to have transcribed it properly. After a while you will be figuring the guitar parts out for yourself, and will find plenty of mistakes even in 'official' transcriptions found in music shops. At this stage being able to read sheet music would only really be useful if you need to be able to play an unheard on the spot (e.g. if you plan on becoming a session musician).
I'm not advising that you actually choose not to learn to read music! But it's not essential. Depends what you want to do