I think a lot of it is posturing and used as a way to send a message to both other states and the Federal government.
On the other hand, wouldn't the municipalities in California that implemented restrictions on capturing and deporting illegal aliens be a similar situation? It is still a self-proclaimed sanctuary area from Federal law, it just hasn't been challenged yet that I am aware of. I think San Francisco was the prominent one I am thinking of.
Wilkinson v. City and County of San Francisco
The Supreme Court on Thursday dismissed, at the request of the parties involved, a trio of cases arising from the Trump administration’s efforts to withhold law-enforcement funding from so-called “sanctuary” states and cities – state and local governments that do not cooperate with federal immigration authorities. Although Thursday’s filings at the Supreme Court contained few details, the dismissal appeared to signal yet another reversal of a Trump-era immigration policy by the Biden administration.