That's for you to decide. I had some sats there and this morning I have moved them to Alby (also custodial). Could move them to Wallet of Satoshi, for instance.

However, I believe it is better to run one's own Lightning node or at least use a non-custodial mobile wallet, such as Phoenix or Breeze. That way, you will have full control over your own funds. I am going to look into that now.

As to what is going on, I don't know their reasons for shutting down the service. From the dry tone of their statement, I imagine that they might be scared of government regulation, or maybe they got a warning, or maybe their lawyers recommended them to shut it down before they get in trouble. But this is just a wild guess; I don't know at all.

You're using a custodial service that is shutting down. Withdraw to another lightning wallet whether that's custodial or not.

Not your keys not your coins.