I suspect there's a couple of reasons...

Firstly, the PO probably makes a fair sum from delivering cr@ p into peoples letterboxes and this makes it worthwhile employing temps to do the work.

Secondly, it really annoys the striking workforce...

Because they have a contract with "Lidl" to deliver those leaflets, normally it'd take palce at the same time as the regular mail distribution. THey have an obligation to fulfil their contract (where possible) despite no other mail to post.

Useless junk to you and me, but to them and lidl's possibly a little more important.

I believe that our normal postman is taking part in industrial action today and have just seen a "stand-in" postman walking up our road with a sack - not full of mail - but full of Lidl adverts - he proceeded to put one through every door in the road - then (presumably) - go home

This makes me wonder - just why the PO employs extra staff - when there is nothing to deliver ??