changing the clustered index on a huge table is often simply not possible due to tlog constraints and/or time. If your existing CI gets you a seek to deleted records that is great for you though!

also, my comments are directed at the (much more common IMHO) scenario where you have a maintenance window to do the massive delete without concurrent-access issues. That brings a whole 'nother level of headache since you need to leave all strutures in place and pay a huge overhead to log all the existing index deletes and you also have to use much smaller batch sizes to avoid long-duration locks causing unwanted blocking.