FishyBoy wrote:At some stage I would like to learn other instruments, the only other instrument I can play is the harmonica and I can sing, but I'd like to learn the sax and piano. Any advice?
Tab will not help you on other instruments. Standard notation can be a useful bridge. Your experience playing by ear & improvising probably will be useful in the long run if you pursue piano or sax or anything else; if you're blessed with a ton of talent, it might be all you need.
You have a head start with ear-playing/improvising, & with that it might be hard to see the value in dots on paper. I was the opposite. I had many years of experience with standard notation & music theory before I realized the value of playing by ear. I thought my training was a hindrance, but it wasn't -- it was my own attitude. Once I got that out of the way, I got a grip on playing by ear with no problems. And I suspect it's much the same if you are coming from the other direction.
If you have the time & the inclination to learn standard notation, it can open up whole new worlds of music, and it sounds like you're receptive to that prospect, so I'd go for it. Your ears can open those doors, but tab... not so much.