I have been wondering this exact same thing myself. I get 16Mbps on HSPA+, and that's more than plenty for everything I do. I could sort of see LTE making sense in tablets (streaming 1080p on HSPA+ is definitely doable, but doesn't leave a lot of extra bandwidth), but I genuinely have no idea why it's (currently) important in phones.
Wow 6 replies here and nobody has specifically called out latency.
I have a verizon LTE device that I tether with from time to time, and the ping times I get to my home server are insane, usually around 20ms. When I tether on my HSPA galaxy nexus, ping times are usually around 100+ms.
Now this could be verizon vs t-mobile and not LTE vs HSPA (or some mix). Verizon is the only/main LTE-supporting provider right now, so LTE and Verizon are conflated in my mind, for better or for worse.
Ahh, a quick bit of googling does seem to suggest that LTE should provide lower latency than HSPA. That certainly is a benefit, much more so IMHO than the bandwidth numbers we see carriers boasting about!
LTE is seriously fast, seriously low latency and makes the experience of using the internet (which is pretty much everything a phone does) much better. A slow connection is frustrating, a high latency connection makes me just not bother, but try LTE and you'll see what all the fuss is about.
Use case is everything you currently do, but faster.
I went from HSPA+ on a Galaxy Nexus (AT&T) to LTE on an iPhone 5 (Verizon), and the difference is very noticeable, at least in my area of the US. HSPA+ was alright but still felt like a cellular data connection. LTE feels just like I'm on a fast wifi connection. It's probably the lower latency that makes it seem like wifi, not just the faster data transfer speeds.
On a counter anecdote, as I've mentioned in the past, my Nexus S on T-Mobile with "regular" HSPA gets faster "4G" internet speeds than my Galaxy Nexus on Verizon using LTE, and latency seems roughly the same.