Do I understand correctly? If BTC is low cost, we can buy it also by lower price? good news
Yes, this is correct indeed!
However, for the current holders of tokens seeing a rise in the market price is usually a good thing because their token value increases. The same effect can be extrapolated to the entire crypto market because a price surge means growth in the market. This encourages new investors, while the existing investors gain more value for their investments. It also drives demand, which is directly proportional to the price.