You have alternatives in most countries. In Indonesia, Thailand and Vietnam, I've found it useful to rent mopeds with <100cc engines. While they are regulated, and while I have a license, very often, I don't get asked for it.
Three big advantages over motorbikes:
a. you're most comfortable driving them at 20-30 km/h (most of them max out at about 50) - this means you get better time to adapt to the hellish urban traffic, are at lesser risk of serious injury and consciously keep away from the fast roads.
b. it's small - that hellish urban traffic is also snailish at times - and a smaller lighter moped allows you better control. It's also better in dealing with roads on resort shores and islands - where the roads may be rudimentary.
c. it's cheap - in highly compact traffic, without stopping distances, drivers rely on predictable behavior... behavior that might be counterintuitive to tourist riders. The odd scratch or dent does happen, and when it does, it's easier on the wallet.
The main limitation is that it isn't a motorbike - it has limited range and efficiency. If you're looking to emulate Che Guevara or Ewan McGregor, you're better off with the best hog (and some handling experience)