Так и есть! Цены внутри Евросоюза зафиксировали на достаточно низком уровне - однако, мобильные опреаторы, чтобы сохранить прибыль, получили возможность поднять цены для остального мира по своему усмотрению - что немедленно и сделали.
Здесь можно тарифы посмотреть - https://callcoinbot.com/#rates и сравнить с тем же Скайпом - разница существенная, особенно для звонков из России в Европу.

One of a reasons - service has been launched as a counter-step to huge increase of a international callшng rates for those who live outside the Europe.
There is a good description concerning that case: https://callcoinbot.com/faq

Вы удивитесь, возможно, узнав, как много людей в мире по-прежнему пользуются телефоном для звонков за границу и даже шлют SMS. )

Latvian-Canadian company launched a Telegram bot - Callcoin, that enables lower rates on international calls with payments in Bitcoin.
http://arcticstartup.com/article/telegram-bot-bitcoin-calling/

Actually there are no messengers (including WhatsApp) that offer services for bot development like Telegram currently does.
Moreover the most popular messengers officially provide information about user activity to PRISM upon request, but Callcoin cares about it's users security and privacy.

Однозначно, с бесплатными звонками Callcoin не конкурирует )
По-прежнему основное количество международных звонков проходит через телефонные сети, вот в этом направлении и идет работа.
После принятия Регуляторами решения, дающего право операторам поднять тарифы на звонки из-за границы в 10 с лишним раз - сделали ответное решение.
Здесь идея в том, что можно мгновенно и дешево (без предоставления личных данных) взять в аренду местный номер и звонить по местным тарифам.

Good questions!
Caller ID hiding feature will drop the the ability of making low cost calls in the most cases.
The regulatory statements in Europe/Russia currently allows fixed/mobile operators to charge the calls depending on a Caller IDs (local / non-local).
So if you are calling to some EU country with EU Caller ID - you have low rate, but if there is non-EU Caller ID or not valid/empty Caller ID - there is much higher rate for such call.
That's why there should be correct and open Caller ID to make cheap calls and that is why there is an offer to rent local numbers - to become local caller.

Look, Telegram is open source and it offers great bot API - try a @callcoinbot to see the cool things behind its implementation + evaluate how convenient to use it. Anyway it is better to try than to discuss. )

There are a lot of destinations still you may not reach except by a regular phone call. So there are no attempts to compete with a something free ... the idea is to make expensive things cheaper, keeping the quality high.

1. Service uses callback technology. Rates are in € (eur), per minute and cover both legs of a callback.
2. Yes, probably is is a fine idea to show a rates in Bitcoin also! Should think about it.  

Currently it is possible to instantly rent numbers from Russia and Latvia. And you may keep the number as long as you rent it.
There is a small monthly fee for renting the number which is automatically deducted from your balance in the beginning of the month.
Those are fixed numbers, so no regular incoming/outgoing SMS can be handled - just voice calls.

I have a guess - there should be a call forward setup on your phone if call is not answered.
Voicemail probably

Bot is cool also - funny and friendly )

There are several interesting ideas behind the project - one of them is to rent numbers from different countries instantly to have local rates instead of international which allows to avoid regulatory restrictions.
Check the FAQ, it is explained in a simple words.

ds5533, уважаемый, мне вот сложно представить откуда у вас такие мелко-криминальные стереотипы о телекоммуникациях и Биткоин - вбейте в Гугл или Яндекс сочетание двух слов - "callcoin telegram". Оцените подход, прочитайте FAQ и вдохновитесь подключить бота для начала.