Why and when should I switch to a grand piano from an upright?

Below is a question someone asked about grand pianos:
Is it essential for learning piano further (meaning the touch etc.)? Does it make you a better and more sensitive player? And is it easier to play other pianos after playing a grand? I’ve played for 10 years now. I have a not-so-good beginner upright and I feel it’s slowing down my progress. I’m thinking of a second-hand yamaha c2 or c3. Thanks.