Yes, you can buy SNT on Coinbase. However, you should be aware that Coinbase is not a traditional exchange, and therefore there are some risks associated with using Coinbase to buy SNT. First, Coinbase is a centralized exchange, which means that it is subject to government regulation. This means that if the government decides to crack down on cryptocurrency exchanges, Coinbase could be forced to shut down.
Second, Coinbase has been known to be one of the most user-friendly exchanges, but it still has its fair share of glitches. For example, in January 2018, Coinbase experienced a major outage that prevented users from being able to buy or sell cryptocurrencies.