Do I need to learn the 'pure' Sinhala script to be understood?

I'm a complete beginner and I keep getting distracted by the complexity of the Sinhala script (especially the ligatures). I want to be able to talk to locals when I visit Colombo, but I’m worried that if I skip learning to read/write, I’ll never actually 'click' with the grammar. Does focusing solely on Romanized Sinhala hinder your ability to learn the language long-term, or should I just embrace the script now?