You'll get some miles and MQDS unlike DL BE fares. But no DL Sky Club access (which requires a partner or DL Premium Economy ticket) and no window C+ upgrades (flights must be DL coded for that) as a DL PM. AF/KL Light fares ex-US have same $199 change fees as DL international BE fares (they coordinate fare filings as part of JV). So they aren't quite as bad as DL BE fares, but there are still some downsides when compared to DL Main fares.