I noticed that journalists often write titles in which they connect two proper nouns (but not only those) with a comma, instead of using "and".
Two examples:
- Poll shows gap between Le Pen, Macron as turnout is seen at historic low
- Cubans seek refuge in Greece, Italy amid economic, political crisis
Is this grammatically correct? Is there a name for such a writing style? Is the main reason here shortening the title?