It is all about conveience vs margin for defects. Work out the best compromise for you. eg  increase handling time so you dont need to go to PO as often, it also increases the chance of a sorting office scan within your handling time for any street box lodged items. If you do get the odd defect its not crucial. monitor this if it gets critical.

ie minimize your risks but there comes a point where eliminating them alltogether is either not worth the cost or time.

It does hurt the pride getting a defect for something you didn't do , ie post late, but it still comes down to a whats best for business decison that you can control.

Ebay call this system evidence based, when in fact it is lack of evidence based.

Ironically Ebays own instructions on using ebay label system still promotes street box lodging, with no mention on how they can defect you for doing exactly as they instruct.

My own experience is that some box lodged items get scanned in state sorting office, and some dont.

Ebays direction here is that they want buyers shipments trackable by the buyer from payment all the way through shipment to delivery. It is the online standard now. pay and hope it turns up sometime is old school for buyers now. The current street lodgement is not realy tracking for buyers but merely proof of delivery for sellers. So going the extra yards is not just to comply with Ebay, but part of providing a better reassuring service to buyers.

Ebay wont come out and say this as they know AP doesn't have the systems in place for your average small seller. The future will be in improved access to scanned lodgement rather than reducing the requirement. Its all just a bit halfe assed at the moment, Ebay are trying to sneak it in by default

Avoiding full tracking will be like holding back the tide of paypal payments over bank deposit was.