The coolest way I have been on IRC was back in 2011, I had just got my first paycheck from my first job, and I bought the most amazing phone I have ever had, the Nokia E7…
The fold out qwerty keyboard was amazing, and made the phone look like a tiny laptop.
It ran Symbian^3 when I got it, but over the short time I owned it (damn pickpockets) I upgraded it to Symbian Anna and later Belle.
I ran Putty touch on the phone, with the keyboard it was probably the best mobile ssh experience you could have back in the day, as you can imagine I used Putty to connect to a Linux server which ran screen irssi.
I felt like such a hacker when I sat in a hospital lobby with my E7 running Putty with screen irssi, I had even set up touch gestures, swiping up and down would scroll in the chat log, swiping left and right would change window.
It remains the coolest mobile phone I have ever had.
There were absolutely native Symbian IRC clients, the example that would have worked best on the E7 is probably BelleChat, I am confused as to why you thought Symbian couldn’t run an IRC client…
As to why I never used it, I preferred screen irssi, as that meant I would have a full log of the channels I was active in even when I was not at a computer.