Back in the nineties this indirection page served to limit my address's exposure, reducing its attractiveness for web‐crawlers hunting junk mail targets. As far as I could tell, this strategy was effective for a number of years. Yes, I had spam filtering too, but when you're on dialup, downloading messages into those filters costs money.
These days that's hardly an issue, but I'm keeping the page for the sake of two of its incidental benefits. It makes it possible for me to switch my preferred address without changing dozens of pages; and it gives me a chance to warn correspondents not to bother sending me MS Word documents. Even if they make it through my filters, I'm unlikely to open them.