>millions of pageviews/month

That is technically correct but does not covey the scale at which 4chan operates. According to http://www.4chan.org/advertise,

    Page impressions per month: 575,000,000;
    Unique visitors per month: 25,000,000;
    Posts per day: 1,000,000; 
    Alexa Traffic Rank: 836 (Global) & 371 (US)
    Quantcast Rank: 305 (US)
    Google PageRank: 6

Makes me wonder if WebM will increase or reduce 4chan's total traffic (when measured in bytes, not clicks).

I can't imagine WebM impacting 4chan anytime soon, it will probably reduce 4chan's load when(if) WebM takes off but I highly doubt more than a small fraction will choose WebM over a .gif in the immediate future.

WebM has caused longer animated content to be posted that wouldn't have been so possible as gifs (the limit is at 2 minutes iirc), so there will still be people posting large files.

Ability to pay my bills

If the beautiful code with 1000 pageviews/month does that, good

If the ugly code does that, good as well. It may be harder to maintain (depending on the circumstances, some "beautiful" code is dreadful as well) which means less money in the bank

Code is usually beautiful until it meets reality with all the exceptions, corner cases, input sanitation, etc

If my business relies on it, option 1, because ugly code tends to be less maintainable and a business should not depend on magic numbers and "LOLOLO...".

If it is for personal satisfaction, option 2. I guess I don't need to explain this one.