Being a week or so late to the party, still: Thank you for posting this. Possibly getting a little off-topic with this post...
Some might think it's really great to see the "points guy" - a frequent flyer - advertising rail travel.
The list right below the picture of the Eurostar trains, called "The advantages of Eurostar awards over airline awards", is great. Though it is being posted in the context of frequent traveler awards, basically it lists the advantages of high-speed rail over air travel - in a blog which possibly is read by many who regularily fly and many who might not have heard about all the advantages of high-speed rail yet.
One advantage the "points guy" forget to mention: in case the Eurostar arrives between 60 and 119 minutes late at the destination (which very rarely happens, but in case it did), then one gets either 25% of the ticket price refunded, or a free one-way ticket for future travel - does any European airline offer that? Answer: no
- all there'll be is "We're sorry for the inconvenience" via the intercom.
When there's an actual choice between high-speed rail and short-haul flights, many will agree high-speed rail is the better option in most cases.
About the actual Avios deal: Of course it's good in case people use their Avios on rail travel instead of air travel. Still the value offered here with the redemption on Eurostar seems to be not as high, compared to some other things one can do with Avios. The value of redemption on Eurostar definitely seems to be higher compared to redeeming them on intra-European flights or some transatlantic economy award where one has to pay $350 one-way extra in taxes and fees in addition to the Avios.
A 9,000 point round-trip Eurostar ticket when tickets cost 69 pounds (approx. $117) each way is a good value. Still, if I can use just a few more points, 12,500 for a one-way economy ticket from Dublin to Boston on Aer Lingus with just ca. $40 in taxes, that's possibly just as good. And if one compares the value of each Avio used when booking an Aer Lingus DUB to BOS business class award for 25,000 one-way with ca. $40 in taxes, the value of each Avio was probably higher (especially with AerLingus adding flatbeds in 2015, and already having the immigration and customs in Dublin, so once stateside one is ready to go). A friend of mine in the Boston area always wanted to visit Ireland, and was surprised to find out that if one is okay with getting a new credit card, making $2,000 in purchases in the first 3 months, and then waiting like 2 months for processing, then one is able to fly in business round-trip for as little as $95 credit card membership fee for a year, and ca. $80 in taxes round-trip with Aer Lingus...
Back to the topic of booking Eurostar: In case one happens to have so many spare Avios, and one doesn't mind the complicated transfer process by phone, of course it is a good use to spend Avios on. Still, me personally, I might already refrain from that just because I think the transfer by phone is too complicated or too much of a hassle (sometimes the hotlines of these award programs make you wait for half an hour etc). And unfortunately, I don't know of so many good ways to get London to Paris Eurostar tickets cheaper. Fortunately, there is a way to buy London to Brussels that might be cheaper than on Eurostar.com - DeutscheBahn offers tickets to and from Cologne, as a combined Eurostar/ICE ticket, and often those are cheaper, for the same Eurostar train. So even in case one just wants to travel London to Brussels, it's better to buy a ticket from London to Cologne, and not use the Brussels to Cologne part, and save some money, and have more flexibility.
For example: Going in 3 days, on Tuesday, May 25, the 6:50 a.m. departure from London is offered for 129 Euro by Deutsche Bahn (to Cologne, via Brussels). On Eurostar.com, the same 6:50 a.m. departure costs 175 Euro (to Brussels only). Or in 2 and a half weeks, on June 11, the 6.50 a.m. departure from London is offered for 69 Euro by Deutsche Bahn. 91 Euro on Eurostar.com. And the best part of it, DeutscheBahn tickets are refundable (minus a 15 Euro processing fee) up to the day before departure. The cheap Eurostar tickets don't allow any changes or refunds at all. And one last thing, with a BahnCard discount card one can save an extra 5 Euro off of all mentioned DeutscheBahn fares to and from London...
So before using any Avios, me personally, I would probably check the fares first, maybe there are some cheap ones, and in case there were then to me it's not worth the whole Avios transfer hassle...