Votes are supposed to be anonymous to prevent retaliation or coercion from strong-arming elections. Logging each vote in a robust way is difficult to impossible to do without breaking the anonymity. If you have a time or sequence number on the vote outside monitoring could match votes to people.

Also ATMs are easier to secure physically because they don't have to be particularly portable. Most units are built into buildings and those that are not are placed once and not moved for years. Compare this to EVMs that have to be moved into place and removed again over a day or two because most voting places are used for that day only then revert to some other purpose.