It's not that unusual. The state of Ohio actually started accepting (through BitPay) bitcoins for tax payments in 2018 -- although they pulled the plug a year later on the technicality that the tax board violated the competitive bidding process for state contracts.

A few Swiss cities and towns have begun accepting bitcoins, and the canton (province) of Zug is following suit this year.

As far as relevance goes, it depends on your interests. Some cryptocurrency media outlets are reporting that the City is planning to allocate up to 1% of its reserves into bitcoin, but I can't locate the primary source for this claim. If true, that could represent a lot of money entering the Bitcoin market. For investors, that's a big deal.

More to the point, I suppose the very idea of governments investing in bitcoin is a big deal. I don't think that's ever happened before. We've seen governments seize bitcoins and auction them off -- they generally don't keep them. Norway's sovereign wealth fund invested in MicroStrategy, who is invested in bitcoin -- obviously not the same thing as buying bitcoins themselves.