I've used them a couple times when it was the only way to book a much-sought-after place to stay. Although it did require a leap of faith (and I would always be VERY careful paying for anything this way) it wasn't difficult and it worked out fine for a couple of apartments.
That said, I did feel like I got burned once when I booked a dive liveaboard boat in Thailand (Phuket, not Khao Lak). Not because they scammed me and disappeared, but because the boat that was shown and described on their website that we had paid for (which was purported to be brand new and pretty luxurious) turned out to not be the boat they had when we showed up in Phuket (the boat they did have was old and somewhat funky); they apologized and blamed it on maintenance delays and scheduling mixups, but it was quite a letdown, and we were in a very poor negotiating position since they already had our money that I had sent to them - not using Wise but old-fashioned bank transfer.
So all that said, I think Wise is a perfectly good service, which can save a bunch of money over old-school wire transfers, and IME Wise will deliver what they promise. That doesn't mean you get exactly what you paid for, though. Years later, I did transfer a good chunk of money to a different dive liveaboard operator (to a business that was based in Egypt, but had offices in the UK, for a dive trip to the Maldives - they couldn't deal with an American credit card – my first encounter with so-called "3-D Secure" payment processing security protocols – all credit cards failed the transaction, so I had to wire them the money). The transfer went fine...and that boat was spectacular! So you never know...I think there's always some uncertainty when wiring money, it's kind of nerve-racking (as you have no doubt experienced).
Good luck and chok dee!