And what's stopping you from practicing for it anyway? A lot of people find unofficial events fun and interesting. The experience of solving bigger cubes can help you improve on smaller ones, too.
THIS MAN says what I've been waiting for. +1, new best bro.
I averaged 17 on 3x3 a few weeks back. I got an SS 4x5-5x5 and exclusively solved both until sub-5 at 5x and sub2 at 4x and suddenly when I came back to 3x I was sub-15. MAJIKZ, U ASK?!1!!!1!11!!! No, just experience with cubing and learning better lookahead with bigger cubes.
Take the Skewb, for example. Or 7bld. Both of the unofficial events are practiced outside competition and even at comps with similar popularity to all other events (and more so than magics and clock) all around the world. Practically, they are just as valid as the other events. However, Skewb is much more likely to becme an official event than 7bld anytime soon. Why is that? Because 7bld is not substantially more impressive than 5bld, or even 4bld. For that matter, any cuber who has tried/does perform bigbld understands that it's not only minimally more difficult, but knows that it's not any more impressive to cuberes than a 3x3 is once you've learned how to solve it. Such events get old. Now, when I see pyraminx solvers? I get excited! Why? Because I don't understand that and it's as mindblowing to me as 3x3 was back before I started.
Conclusion? New, interesting, original events are more tempting for the WCA board than just another cube with a few extra pieces with the exact same solving mechanics as the smaller sizes. This is what we cubers see: 3x3? X pieces. 4x4? Y pieces. 5x5? Z pieces! 6x6? Hmm. I'd say that doesn't look like a significant higher number than Z so we'll label that as Z. Same goes for 7x-10x and beyond.
Basically, don't stop doing unofficial events, but don't get your hopes up on events that are clearly just boring to the cubing world as official. The reason we don't exclusively do 3x3 in comp is because it gets boring after a while. I want Skewb!