The use cases of Bitcoin and Crypto Digital Currencies are varied and change constantly.
Bitcoin as a medium of wealth transfer is an appealing use case, as it undoubtedly offers lower fees than Western Union or other similar payment processors that prey on unbanked consumers from lower socio-economic nations. Use as a real world currency is currently limited however due to volatility. Bitcoin volatility has been trending downwards over time, but is still much too high to be used as a stable currency for everyday goods purchases. Nonetheless, there are many providers that now allow you to pay for everyday goods with a bitcoin denominated debit card, but consumer demand has been quite low due to the volatility issue.
More recently, the use case of Bitcoin that has gained the most popularity is as a digital 'store of wealth' or as a 'digital gold'. As Bitcoin has a defined supply that will never change, many see it as an effective modern hedge against inflation in much the same way people rush to gold when volatility hits.
Waiting for a 'tipping point' per se with digital currencies doesn't make a lot of sense to me. If you believe in the technology and can foresee a world where cryptocurrencies become an entrenched part of the modern financial system over the next 10 years, then the current price is less significant. In that position, I believe the best tactic would be to invest using Dollar-Cost Averaging method.