src vs src_host and dst vs dst_host

What is the difference?

DNS resolution.

https://www.wireshark.org/docs/dfref/i/ip.html

ip.src: plain IP address
ip.src_host: reverse resolved hostname of that IP address

See also the following questions/answers:

https://ask.wireshark.org/questions/14126/tshark-not-resolving-names-and-not-showing-protocol-as-text-when-exporting-to-csv-file
https://ask.wireshark.org/questions/13310/how-to-enable-the-tshark-name-resolution-while-exporting-to-csv-from-an-already-captured-pcapng-file

Regards
Kurt