I'm learning German and was wondering if I could completely drop ß (Eszett) and replace it with ss in all instances where ß is used. I know that the Swiss don't use ß. Is this practical? Can this become a problem when communicating with Germans?
You are creating ambiguity. After the latest spelling reform, people assume ß makes the preceding vowel long. In German long vs. short vowel is always significant to meaning:
Maße ← long a — measures
Masse ← short a — mass
In Switzerland, people live with that ambiguity. It's only a minor obstacle in Swiss German, which is a challenge of its own.