I find I have no great desire to set my money whirling around the tree, even if it should, in time, come back doubled and redoubled.
First of all, it seems to me that money should be a reward for honest effort. I am properly paid -- and paid well! -- for enchantments, for healings, and (paid poorly! I am not that good!) for embroidery and smithwork. More money, I suppose, is deserved for risky endeavours, such as adventuring: but the risk multiplies the reward due to the effort; it does not add it it. Pure investments of money, such as giving a wine-trader ten thousand lozens for a long trading trip and hoping that my share after it is done is eleven thousand, are no significant effort on my part, and do not particularly fit my dignity as a noble of sorts.
Second: Nor even my convenience. I do not wish to be forever fussing to find good merchants to invest in, fretting about how their commerce is going, losing money when I guess wrongly, gleefully noting a few more lozens when I guess rightly. Bankers do this sort of thing, which is why banks and bankers are wealthy. It is not how I wish to spend my time... and, though time is plentiful, my special tricks with time will not help much for this.
Third: La! Which is to say, my primary concerns are, I think, the safety of prime civilization from Vae; my friends and companions; enchantment; the cause of transaffection. Perhaps I am missing something, and probably I should count fine dining among them. These are enough for a somewhat over-full life (and, with fine dining, an over-full belly as well). Fussing about money and investments is none of these; money is a means to an end, and, as an enchanter, I generally can earn more, honestly, at need.
Besides, I dread to imagine what sorts of Doom I could get in, if I indulged in investing.