AFAIK, BTC address never expires and in Binance you can only have one deposit address for bitcoin so if they sre changing addresses of everyone for some reasons then its due to development of their platform or something like that so why we should be worried about?
Some may have been using Binance as a wallet. Some may receive funds on such addresses. Some may have published such addresses as donation address.
The address will not expire ever, but, depending on what will Binance do internally, it may be that they will no longer use nor watch the wallet(s) having the old addresses, hence the user accounts will not get funded if money will come to those addresses.
So for people using Binance as an exchange it's not a problem at all. But those using Binance (account) as a wallet... may get to learn on the hard way to use their own wallets as wallets.