Think no one can doubt the gold days of IRC are long past, but I know some communities still active, including bitcoin one.
But still nothing compared to the old gold days.
That is what I felt like towards the end of my IRC days. Most of the knowledgable people I knew back then all left IRC once all of the networks we typically used started getting overrun with xdcc bots and a lot of the networks started getting into policing & politics on the management side, which just didn't make it fun anymore. Nonetheless, I met a lot of interesting people on IRC back then.
I still use IRC for multiple things including BTC, reprap, hackerspaces, arduino. Most channels I use are on freenode. As far as BNC servers go most people including myself are just using a raspberry pi setup. Its cheap, uses little power and pretty reliable.
I assume this raspberry pi setup is located somewhere else… or why run a BNC in your own house? The main reason people I knew used BNC's were to protect themselves and fully hide the IP/location they are connecting from, primarily to protect against script kiddies & dos/ddos attacks. I realize most networks now probably mask IP's, but there are still plenty of people (IRCops, admins, shell providers) that could see them.
The people who use IRC now tend to be the people who want to self-host that kind of thing. Also Freenode now has a web client, so my guess is that it would be difficult for a paid service to differentiate itself well. You'd need to have a lot of value-add features beyond simply running am IRC bouncer.
I've only used ZNC, not BNC, but I presume BNC also has channel buffer replay support. In addition to automatically repaying channel buffers when a client connects, you could store them and make them accessible on a convenient and searchable web interface.
Another feature you could add is proxy OTR. For people who connect with a client that lacks OTR support, you could make the bouncer negotiate the OTR for them and relay the result. This isn't a thing a user should do if they can do the OTR on their side, but it's an improvement over not using OTR at all, which is what they'd do without that service.
That makes sense, I could see the self-hosting option working for people. There were plenty of people back then that self hosted IRCd servers as well but mainly for private networks, anyone who wanted a public network typically went to a shell provider to be fully protected from denial of service attacks and to ensure their networks/servers had the highest uptime, availability, and bandwidth.
Back then it wasn't as easy to have high-powered linux machines sitting in your house to be able to support the amount of memory & processing power needed to run an IRCd process hosting 1000's of users….. not to mention the bandwidth - a lot of people still had dial-up or extremely capped upstreams at home. (until we all figured out how to get around the caps)
but obviously not too much bandwidth involved with self-hosting BNCs
We ultimately started using psyBNC for our BNC accounts to get a better feature set. The basic BNC client, without developer support, didn't grow with the times!
I do like the idea of having a web-searchable interface for the channel logs but not very familiar with OTR, which I am assuming is off-the-record messaging? -- I will have to do some more research on that one.