I agree with Rowanalpha that this drawback is odd. I've no idea what the point of caring about this particular condition is supposed to be, flavour-wise or gameplay-wise. It just seems to be a thing you could design cards to care about without any real reason why you would do that. Just because a card design works and is balanceable does not make it fun or interesting.
I think it's also going to be a confusing condition for a lot of players. I reckon most players even will not know what this even works with on first look. I certainly didn't. My first thought was 'how many cards does that even apply to?'. Newer players I'm sure will struggle. I imagine some newer players will guess this is supposed to work with basic lands because they don't have any rules text. Taking one look at the google search results will reveal that plenty of people have been unsure about whether fetchlands count as mana abilities and I'm sure plenty of people as a result would miss that they work with this.
Mana abilities is a complex term to include on something as staple as dual lands and I think this condition is going to be more confusing than most usages of the term which are already relatively sparse.