"This problem may only be applicable in a limited number of scenarios, namely while the payment is in-flight and mainly for payment routers. Quantifying the magnitude of this problem can be quite complicated, as it depends on the specifics of the channels involved."
"In general, it probably is reasonably safe to route small value payments most of the time. HTLCs provide lower protection when the fee rate increases, however HTLCs may still provide some limited benefits even when they appear somewhat uneconomical."
"Determining exactly when the payment value is too low to be secured by the HTLC is complex and depends on the unique circumstances of the channels involved."
"In our view, this problem is largely theoretical anyway, compared to the problem of hostile entities just initiating expensive non-cooperative channel closures when fees are high. This wider griefing issue is larger in magnitude, than the problem of routing payments too small to secure."