The operative acronym here is IRC.
Without arguing both sides, advantages and disadvantages--IRC protocol is meant to be just for chatting. If you want webcams, feel free to visit Yahoo, or make an alias that runs NetMeeting or something. But for your chatting need, stick to mIRC.
IMHO, mIRC doesn't need another thing to bloat it and slow it down. Support for webcams can be scripted (and has by several). If you want it, just load the addon.