I'm confused as to what kind of companies can launch an ICO - only blockchain based companies that have some inherent use/tie-in of tokens/coins or others as well? For example, I just saw the ethereum based ICO of Kik messaging app where the tokens can be bought/earned and further used within the messaging app. However, Kik is not something that I would consider a blockchain company. On similar lines, can any company or business launch an IPO provided it finds a way to issue and use coins? For example, can a brick and mortar business like a restaurant launch an ICO? Where the tokens could be used to order food online? Please share your thoughts.
You have stumbled right into the can vs. should argument for creating tokens. Ethereum is an open platform where anyone can create a token, for any purpose. But you then have to ask the question "Who would buy it?" or "What value is it?". Anyone can write a smart contract that defines a new token, and if you have ether to spend on gas, can create it in the blockchain.
So, to no, a company does not need to be "blockchain-based". Yes, a brick-and-mortar restaurant can launch an ICO. Whether or not the tokens could then be useable to order food online is a question of how that restaurant chooses to design the token to operate. If the tokens have no use other than "company XYZ made them" then likely they'll not be very popular, but the company won't be prevented from trying.
It's the same idea as me printing out "brownie point coupons" in the real world and handing them out to people. I'm free to create such coupons. But what can the recipients do with them? Probably nothing. Creating a use for their tokens is the onus of the entity creating the tokens, and time will tell which of them are successful in that.