YC is lowering their investment, still worth it?

I think you should apply, because just applying will help you straight out a lot of things about your ideas. If you get accepted, then you get a first validation that your company/idea/team is worth at least U$1M, and then you'll be able to think again if you want to join or not.

The spirit driving YC is not for everyone, but many of the processes they put you through can be very valuable. Remember that their target is to get 10X return, so if they value your company at 1M today, they are expecting to see it grow to 10M in ~1/2 years. Just keeping this in mind will help iron out your business plan, growth strategies, etc. provided that this growth rate is what you are after.

What's the value on YC's network and the branding? Amount of people adding 'YC Startup School' beside their startup name after attending the free online course says that the value for actual YC incubation & investment is very high.

Then again, YC is not a magic bullet. There are over 2000 companies in which YC has invested and many of them don't exist anymore- http://web.archive.org/web/20200613190117/https://www.ycombinator.com/companies(Archive link, as original URL now automatically filters by top companies) but we usually talk only about 100 top YC companies - https://www.ycombinator.com/topcompanies/.

So, if you are building a good product, YC can accelerate the growth, the brand can bring in further investment. When compared to other accelerators, which are just camouflaged co-working spaces; YC seems to be a good bet even with limited investment.

YC (or any other startup accelerators) often offer more than the money, for example:

• Tied community, which make helping each other easier (i.e launching)
• Adviced from people with experiences
• Connection with people with reputation, which might help you

In case you have already asked whether, a startup accelerator is suitable for you, and the answer is yes. Then you should try.

If it is really suitable for you, 25k less often not a problem in a long term

I think it's fair considering that the cost of running the startup is a bit cheaper since many companies will be participating remotely for the foreseeable future. I think most people who apply aren't as concerned about how much their company is getting valued by YC since most startups raise money at a much higher valuation. As for the reasons, it could be because they want to fund a few more startups in the next batch. Or it could just because they can, and people will still apply regardless.