i'd say it's quite important. it may happen that the usage of the chain at the very beginning is not high i.e. that the capacity is unused, but it helps (by means of not limiting) development of dApps and implementation for usecases other than payments. e.g. a chain with high tps can be used for data storage, IoT type of data storage, different data tracking. on the other hand, high tps implementation from the very start will help the code dev team to focus on implementation of other features, instead of constantly increasing the transaction throughput as the usage of the coin grows.