Voice chat is just a really nice feature both to communicate effectively and to socialize. I find that anytime I'm using voice chat in any capacity I communicate a lot more with people whether it's relevant to the fight or not. I never really had this problem on FFXI because the pace was so slow. I could just type whatever I needed to during the 15 second cast time or during the breaks when I couldn't cast because I had too much enmity or was on stun rotation but not up next, etc. Such situations never occur in FFXIV. If you're not at minimum pressing a button every 2.5 seconds you're doing something very wrong, so there's very little room to type much of anything.

That said, sure you can get around it, and by the time your group knows content well you probably don't even need it, but it helps a lot in the learning process.