This has been suggested a ton of times. mIRC's language is unlikely to be any faster if it didn't go through the UI, that's not the bottleneck-- the actual language implementation itself is. For example, you're unlikely to ever get very far into a performant game without native support for stuff like arrays, floating point math, OOP features, etc. The general consensus is to use a general purpose language, and not mIRC, for your tasks.
Even if you did get a compilable version of mIRC scripting, it would likely take a really long time to create (and be fast); you'd have learned another programming language by then. Also note that mIRC is really not significantly easier when it comes to the types of tasks you're describing, at least, not in 2016. mIRC is good at one specific thing-- dealing with the IRC protocol; it is not any easier to use than say JS, Python, or Ruby, when it comes to anything else.