Was kinda curious about the pricing and honestly the pricing[0] seems like one digit less than I expected. 10k JPY for the number, then 1k JPY per some of the various options (stuff like routing seems to be literally "we set up a phone tree and at the end of the phone tree we just dial a number you give us")
So it sounds like in the end you need to pay 10k JPY per queue + an extra bit of money to wire it all together. Maybe with Twilio you can set up something similarly fire-and-forget but "I explain to Docomo once how to set up my phone tree" sounds nicer than "I set up a twilio... thingy".
I'm sure somebody out there has at least considered being the layer over Twilio that just offers some of these straightforward services... but... toll-free numbers on Twilio cost 27 cents a minute in Japan. Sounds real close to that 33 yen.[1]
[0]: https://www.ntt.com/business/services/voice-video/freedial-n...