I assume you are referring to a physical log book for documenting your flights since the Explorer app automatically creates a telemetry log on your device with the respective Google map overlay if you had a map loaded into your device or you were generating the map in real time. So in a way you are logging every flight. But of course you can delete those logs from your device using the app. But NOTE, if you SYNC your logs to the Cloud, those flight records will remain on the server permanently with no way of deleting them in the future. IOW, if you happened to have a flight that was not up to par with local or government regulations as a case of pilot error you wouldn't want that sync'd to the cloud. Courts are allowed to subpoena any company for internal records in the event of a legal action against the pilot. So it would be best to delete that(those) log(s) from the app device prior to sync'ing.
From a USA business owner stand point, small businesses are required by the IRS to maintain a Travel Log on their vehicle use, what day, start/stop mileage, and notes about reason. This justifies the deductions on your tax return related to the vehicle like fuel, maintenance, insurance, etc. And supports your position in an audit.
I would recommend that if anyone is using their drone(s) in a commercial Part 107 venture as a business (at least in USA) that they also keep detailed log book records on the drone use. Not only to defend oneself in the event of a tax audit but also as a secondary record that can protect yourself from 'mistaken identity' if there was some illegal incident in an area you may be flying in. The hard cover log book I keep is a great field record for documenting where and when I was flying but I also take notes on the things that were my objectives on that flight day. Like testing out and practicing features of the software and hardware, what I drained each battery and RC down to that day and every time I charge each of them even though the app is keeping track that. Software and its database can fail and lose everything. My log book is a backup since battery cycles are not part of the flight log.
If I am just going out to get some flight time practicing my 'cinematic skills' of camera moves and placement I may have thought of some things in advance to try so I'll put them on a post'em note and stick them in the log as a temporary reminder on the day I go out.
The name of the game is PROTECT THY A-S-S! You can't be too thorough in today's sue-crazy world. Even if you are a recreational pilot. There are risks for everyone. That is another discouraging thing about taking a drone on vacation to a foreign land. You may end up with an extended vacation with free room and board if you violated their rules. Or at least leave with a much lighter wallet.