Long range artillery, missile or gun

I have been playing with some extended range naval guns and found in the HCDB2 DB three versions of Vulcano extended range 5" munition.

see https://electronics.leonardo.com/documents/16277707/0/Vulcano+127.pdf?t=1671440934942

In HC terms two are Guns, one is a missile (speed about 2200 kts). When I used the missile I thought 'wow, so slow', but then when I started to think about it the speed was quite correct and more realistic than the instant gun hit (or miss), so I started to wonder for long range artillery should we use 'missile' and not 'gun' weapons?

I'm interested in the new Kingfisher concept for ASW including the delivery of small depth charge and sonar buoys and thinking if use 'missile' then could use an asroc style weapon.

see https://www.navylookout.com/the-kingfisher-gun-launched-anti-submarine-munition/

What do people think?

Don