Yay JSON export isn't premium but csv is. Lets just move some data...

trello_2csv.py

import sys
import json
import csv


def main():
    input_json = sys.argv[1]
    output_csv_data = [['name', 'lastdate', 'desc', 'shorturl']]
    with open(input_json, mode='r') as ijson:
        data = json.load(ijson)
        cards = data['cards']

        for c in cards:
            output_csv_data.append([
                c['name'],
                c['dateLastActivity'],
                c['desc'],
                c['shortUrl']])

    with open('trello.csv', mode='w') as output:
        writer = csv.writer(output)
        writer.writerows(output_csv_data)


if __name__ == "__main__":
    main()