Yes, assuming direct pricing/incentives stay similar to what they are now, the primary advantage to purchasing before the start of your UY is that you get all of the points from the current year which can be sold back to Disney for $20 pp - magical beginnings. On 150 points, that’s $3,000 off. Assuming they offer it next year, you could still get it, but then you wouldn’t have any 2025 UY points to use and would have to wait until October of next year for new points.
Of course, by waiting to buy, you’ll also pay less in member dues since you are liable for those on a prorated basis the day you sign your contract. For Poly, 150 points will equate to about $100 per month in dues. So every month you wait, you’ll pay about that much less in dues. Pretty small compared to the $3,000 savings with magical beginnings IMO.
Only caveat is none of us know how pricing/incentives will change. Best bet IMO is probably just incremental adjustments (mostly increasing the price) but you never know if a month or two of slow sales might cause a round of incentives to jump.