"[S]ignals the power of compounding" -- only to unsophisticated (frequently, retail) investors. Institutional investors always have historical data that is split-, and even dividend-, adjusted. If I had to guess, refusing to split is like a form of virtue signalling, nothing more. When I was a kid, IBM usually had a high stock price, over 100 USD. I never understood why; nor did my father, a stock broker.
"Unsophisticated" investors see the big number and the price history (which is much simpler without splits) and see the power of compounding plainly. There's not much more to it than that.