the most worthful way to use RPs is to accumulate 100K and exchange for 100K satoshis, without any doubts. However, not everyone has patience, hope, perseverance, enough money or referrals to reach that amount before using it, so they simply collect some thousands and start using it for extra wheel's spins or RP bonus. Since those RPs were given "for free", the mindset of "it's better than nothing" is common among many users.
That is, only if you are not gambling an insane amount. If you do gamble in an insane amount then you could calculate how much your reward would worth if you turn it into satoshi, maybe that will be worth a lot more than what you buy as a reward, but if you are in profit then you could just get something instead.
I am not saying that you should do it, I didn't calculate what the rewards are worth, and if the worth is over than the item then you should turn that into money only and not look at anything else, and most rewards are older generation electronics as well so they do not even worth it all that much. However, if you feel like you could profit, and you are someone who gambles a ton, then you could just take them too.