Cryptocurrencies are more than just a medium of transfer of value. With blockchain technology you can eliminate intermediaries, allow parties to collaborate more efficiently, create disruptive new business models, add visibility to supply chains, develop more secure payment reconciliation solutions, assist with dispute resolution, deliver end-to-end transparency for systems … the list goes on. Any application which leverages the properties of the technology (decentralisation, transparency, immutability, pseudonymity, being open source, cryptographic security etc.) is a solution to a problem which can use the technology.
Blockchain development is expensive, time consuming and difficult. If you want the security of a public chain, you’re also going to have to find a way to distribute the cryptocurrency and convince enough people to secure it (see What do “mining” and “staking” mean?). A Blockchain as a Service (BaaS) is a platform fuelled by a cryptocurrency which allows users to utilise the technology without having to build it from the ground up themselves. A BaaS is usually a platform with features and services native to some underlying blockchain. All a user has to do is customise the service to their particular application, thus having the benefits of blockchain technology at their disposal with a lot less of the hassle. One such common feature of a BaaS platform is the ability to issue tokens (see What is the difference between a coin and a token?). When issuing the token, the user can tailor it to fulfil whatever requirements they wish in some application. For example, the token could behave as a security, fulfilling that function of a coin but with added fungibility and without all the hassle of setting up and securing a blockchain themselves.
Here’s one way to think about BaaS: Baas is to blockchain what Microsoft was to computers. Microsoft would go to a company and say, “hey using a computer you can make your business better, sell more products, dream up new products, significantly speed up systems and processes to save money etc. and best of all we can sell you a computer and show you how to use it”. A BaaS wants to do that but with cryptocurrencies and blockchain technology. Just as how these businesses aren’t going to build their own computers and develop all their own software, nor will they want to build their own blockchain and develop all its features by themselves. It’s a crude comparison, but hopefully it highlights the reason-for-being for BaaS.