Water purification tabs, straws, and bottles are not practical unless you are in an extreme environment to find clean water (hikes, for example).
- They tested awful. Iodine tablets have an awful taste after. We often use orange flavored powder to hide it.
- They are expensive in third world countries. You have to use one tablet per liter, and it costs about 10 cents USD per tablet. In comparison, you can buy a 1L plastic bottle of water for 30 cents.
- it takes about half an hour to work, so you can't use them immediately.
- Even if you buy those straws, they have a maximum lifetime before you have to replace the filter (about 1000l). You will need to replace about twice a year if you were to use as the daily drive.
Or SODIS sunlight disinfection.