You can use interest rates and rates of return to convert between stocks and flows of money (or more generally, things we measure using money, like stakes in companies).

If you add that most people have some common sense notion of what reasonable or achievable rates of returns look like, then what you said was just a bit vague and implicit, not necessarily a sin of dimension.

For a similar example:

An CPU designer might tell you that one clock cycle is 'this long' (where she stretches out her arms in front of her). She's not committing a sin of dimension, more likely she's talking about how far electronic signals travel during one clock cycle.

Could be worse

https://xkcd.com/687/