There is what I like to call The IRC Problem, which is that it takes a bit of work to really make IRC into an awesome, persistent chat environment.
First, you need to be persistently connected so that you don't miss messages when you're not actually at your computer.
Second, you need a decent interface to use when you are actively reading or chatting.
Third, it would be great to have the same across all devices (phone, tablet, laptop/desktop), with everything syncing correctly. If you read some scrollback on your phone, you want your laptop to also know that you already read those messages, and vice versa.
It's certainly possible to achieve all this with irssi and a combination of other techniques. However, you can also use something like IRCCloud and get every problem solved at a very high level of competence immediately, plus a bunch of other stuff (like push notifications and embedded social media, images, videos, tweets, pastebins, etc.).
It's up to you. For me, I really just want everything to work and I don't care at all about doing it myself. It's a means to an end. The $5/month fee is not important to me given the product quality. I sort of liken it to Dropbox -- it's not about doing something that couldn't be done before, it's about just making it streamlined for those who don't care to do it themselves.
> First, you need to be persistently connected so that you don't miss messages when you're not actually at your computer.
I consider that a feature of IRC myself. I don't need to be wired in at all times and read eveerything everyone says. If I'm not there, I'm not there, and if there's something important I really need to hear, I'll hear it when I'm there. If I don't hear it, it never was important.
There is memoserv in many IRC networks that does relay messages when you come back online. I have seldom had important messages relayed that way either. Most conversations are not that important.
I don't see IRC as something that should follow me everywhere across all devices. It's like radio or TV. Turn it on, turn it off. Not on all the time.