Jack,
Rubber roofs are new to me also. Essentially, my roof is also domed plywood, but instead of being covered with an aluminum sheet, its covered by a "rubber" sheet. The "rubber," is apparently a highly UV resistant material specifically engineered for use on RVs. Up close it looks a lot like heavy weight canvas stretched tight across the roof. It has a rough surface texture, but is non-porous.
When first introduced, this roof material was really pushed as the new miracle material for RV roofs. Well it hasn't quite worked out that way because some drawbacks turned up over time. Like the sensitivity to certain chemicals, chalking if not periodically "treated," gray streaking if the chalking isn't controlled, etc. The good traits include ease of patching (if needed), lack of corrosion, significantly higher UV resistance (compared to fiberglass), and a few others including lighter weight....
Jack, if I had my druthers, I'd prefer the roof you have. Our '69 Bon Voyage has an aluminum roof that has held up, without any maintenance, VERY well for over forty years. I've never even painted it with the sealant stuff you mentioned.
Jim