If the seller asked you to pick up, he obviously had the item so the item does exist.

It's not a fraudulent listing for a non existent item which would be a scam.

Yesterday afternoon the seller did send me a msg and asked if he can cancel the transaction and asked me to pay on pick-up, 

He asked you to do this  as he probably isn't signed up for managed payments and there's no protection for you if you pay cash so:

1) He  wanted cash 

2) Cancelling the transaction means he doesn't have to pay eBay fees.

So a bit of a scammer anyway.

"Yesterday afternoon the seller did send me a msg and asked if he can cancel the transaction and asked me to pay on pick-up" 

The seller offered postage.

This wasn't a pick up only item  where a seller may  "suggest" cash on pick up

It's a deliberate offer to trade outside of eBay, avoid fees,   and as such,  is reportable to eBay