If you can get away with a day-bag of reasonable dimensions, then do so. Make sure you don’t pack anything dangerous (Bowie knife, TNT, bottled water, 125g tube of toothpaste) in case you have problems with customs/security and get mistaken for a terrorist.
Quite a few airlines will let you check-in in advance – often days in advance – if you only have personal luggage. As long as you can print out your boarding card, you can skip the whole check-in queue at the airport. This means you can get away with arriving later and have that bit less stress. Plus, your luggage can’t go missing, and you can walk straight out at the other end. No having to stand for 15 minutes at a carousel wondering if your rucksack is in Bahrain.