For Intel(R) Rapid Storage Technology (or Intel(R) Matrix Storage Manager) there is no difference if you use a hard drive with such recovery options or not since it does not use any of them. The SATA controller will have a time out of approx. 7 to 10 seconds too using Intel(R) Rapid Storage Technology.
Thanks but then in this case it'd mean the non enterprise drives are going to be dropped from the RAID if the SATA controller itself will also time out after 7 - 10s. The TLER feature is exactly to prevent time out and just indicate that the requested block on the disk is not available so the RAID should know that it needs to reconstruct elsewhere, then move on rather than waiting indefinitely.
In other words, even for the RAID implementation Intel has, enterprise disks are still required. Correct?
They are not required, since Intel(R) Rapid Storage Technology will not pay attention to these recovery features. It will timeout anyhow after 7 to 10 seconds and drop the drive if it does not respond.
If the disk gets dropped out of the RAID, that's exactly one of the case to opt for TLER features in enterprise drives. Pretty much the behaviour you have said is exactly what TLER is for.