1) you won't attract any follow-on investment capital;
2) your original investor will be angry that you're sitting on a pile of money that is doing nothing;
3) you will likely grow slower than your other competitors. in some markets, this is death, in other markets, this is fine.
Patreon had nearly 500 staff before layoffs. Now has about 400 staff. You may have a hard time understanding what all those people do, but I suspect they're all quite busy.