[bogomipz]

It looks like there is a rail option between Brussels and Strasbourg which is just under 4 hours[1]. That's four hours where you can work the entire time. With the boarding, flight time and travel time to and from the airport what is the actual time savings here 1 hour? And if you could work the whole time on a train it sounds like a non-issue since this schedule seems to factor in two of the 4 days as travel days. Also why Frankfurt? I realize Frankfurt is an airhub but why would this be a convenient location?

[1] https://www.rome2rio.com/map/Brussels/Strasbourg#r/Train/s/0

[nikanj]

Because frequent flier points get you nicer things than frequent rail points

[dewey]

For a short flight like that you'll get almost no points and you'd get more by booking a hotel room with a credit card.