It's not of course the "only" method I myself will accept but I admit I'll request it to prevent funds from being held for up to 21 days.
And I'll pretty much demand it with Int'l sales: entering tracking info on a Int'l transaction is something I do my best to avoid at all costs.
Reason being: some Int'l parcels can take up to 30 days or more to arrive meaning funds from that transaction are held until tracking shows having been delivered.
At least that's the case with my account.
That's a huge issue for me: the watch I had on my wrist a few days ago arrived to me with signature required via Registered Int'l.
To this day that tracking info shows the watch is still sitting in the customs sort center in Chicago: were the tables turned in that deal I'd still be waiting for the funds to be released to me.
Heaven forbid a package gets lost: I'd have to cut flips through rings of fire to get the funds released and repeated calls to paypal draws attention that I don't care to draw to myself.