My B&M taillights only the 4D toplight senso had a blink mode..
and that was the senso daylight into a tunnel mode,

their flash interval is at much lower frequencies than the Asian made ones ..
IMO following someone with a higher frequency blink is annoying ..

I change streets or just stop and let those folks go ahead..

I Acknowledge the batteries last longer in blink mode than steady , but making electricity
as I go ,with a hub dynamo, that issue goes away.