Yea, foot retention is good for sprints, but who is doing sprints? Who are sprints important to? Almost nobody is the answer to that, and the answer anyone with a brain would get from the Dylan Johnson review of research on the subject. For the 99.999% of the population that is not Dylan Johnson or some other pro trying to win major races and to whom sprints are meaningless, flat pedals are the way to go.
Flat pedals are also more safe in a crash because you can get your foot down on the ground more quickly to help recover, it is easy to find stories of riders getting serious injuries because their foot was caught in a strap or clip preventing them from using their foot to keep the bike up, or making it so their knee hits the ground first.
The most common thing on this forum is the deeply flawed point that because pros use something for a fractional performance gain, then the general cycling public needs it. If that is the only argument you have, then you don't have one.