The difference is that on the SL chain you'll have to consider the risk that a transaction gets stuck because of full blocks from time to time. This also increases the risk of a bidding war and the potential allowing of replacing or even maliciously double spending transactions.
On Bitcoin Cash your transaction is highly unlikely to ever get stuck since the blocks are never full, nor will they be made so artificially to promote changing the scaling roadmap.
With encouraged RBF (under full load or not) the rules of the game change. It becomes more likely that transactions become replaced and this makes zero-conf transactions much more risky for all parties.
Look, I know it may all seem ridiculous on the surface. I've been there too and it's not like information has been readily available so far. Ask a stupid question on the wrong subreddit and you can get instantly downvoted or ridiculed etc. But the information is out there.
RE: What I think makes Bitcoin Bitcoin, and why I think Bitcoin Cash is Bitcoin