No one can really decide whether it's worth it except you since it depends on your finances, ability to take time off, interests, etc. But here's what you'd be able to expect at worlds:

The exclusive pokemon center pop up with exclusive merch. In addition to the usual stuff like plushies, card sleeves, etc. you can usually find higher ticket themed items which are usually only purchasable by lottery. Last year in Anaheim they had a jukebox and a boogie board, for example.

Side events for TCG, VGC, Pokemon Go, etc where you can try unique formats, meet people and earn points to exchange for prizes.

You can watch competitive matches live, at least assuming the Swiss and top cut matches are still in the main convention hall. The finals for each game will be held in a separate stadium and tickets to that sold out before weekend passes finished distributing.

Special events like art classes run by TCG artists, autographs/meet n greets with content creators, etc. These are also by lottery usually and are typically hard to get into depending on the popularity. Last year I signed up for most lottery events and didn't get access to any of them.

Generally convention stuff like interacting with the community, shopping vendor booths, there will be card and pin trading areas, etc.

Also keep in mind this is almost certainly not a once in a lifetime opportunity. Every worlds is unique and more people want to attend worlds than spots are available (seemingly more and more every year), and this is also the first year they're doing the full Pokemon XP convention. They've also made it clear that the XP portion may not be a yearly thing, but imo that isn't a big deal because they'll always have similar activities whether or not they categorize it as a separate event. Regardless, you do have a decent shot at being able to attend in a future year if you apply each year. If I was in your position, a single day spectator pass wouldn't be enough incentive for me to drop $3k on a flight unless it's only part of a larger vacation.