In order to reach 190 satoshi per free roll, you already need to wager quite a lot and with the house edge, you will always loose money. You also get RP that compensates its a bit and based on the premium membership also a small cashback, but it doesn't add to the risk in my eyes.
I wagered a lot during the days when you also had deposit bonuses (Golden Tickets), so I built up a LOT of my wager from those old days and am still enjoying the bonus until today.
If you play it well, using the deposit bonus, the interest, the extra cashback from premium, and only wager during 5x or 4x RP bonus, plus always taking the rakeback% bonus (when you wager you get 1% of it as cashback if you agree to wager even further for it).
Played smartly, you can lower that house edge a lot, almost to the point it's no different from playing dice at other sites.
The benefit? Those extra freeroll sats. I don't roll all the time but I last tested it about 2 weeks ago, used all my balance to buy FUN. I built back 30k sats in less than 14 days (enough to again earn interest) from freeroll plus WOF alone.
I'd say long term, that bonus is worth it.
That is the correct strategy and I would add to it the new benefit which is not mentioned here or you overlooked it.By gambling nice amount of Satoshi during those promo times and also during 5x or 4x RP bonus can also increase the number of WoF you can exchange to RP daily.I always had 1 WoF spin for as much as I was playing 5000-15000 Satoshi which wagered were like 150000 or a bit more.Once I started playing like 100000-200000 Satoshi during these times that bonuses were active and wagered amount was like 0.03-0.05 Bitcoin for a couple of days immediately after since then I have 4 WoF spins to exchange daily which is a good number.If I continued to play probably this number would be higher.
So yes in the long term bonuses are very much worth it.