I don't have a Rallye but I do have a 2018 TE. I bought it with the engine bars (silver). However, I am removing them at the next service and selling them (already have a buyer). Instead I'm going to fit X-Head machineart covers. I know, I know, I have read the threads about bolts shearing off, I have emailed Machineart and they assure me they bolts I have are the new ones, and it is also why I'm getting BMW to fit them for me at the next service even though I have torque wrenches and have some mechanical abilities.
I changed my mind (WRT to having bars) because all but one of the anchor points also attach to the chassis. If you have a large spill, there is a distinct possibility that you will bend the chassis and it won't save your cylinder anyway. Even a small spill with the force at the right angle (doesn't even have to have a huge force) could potentially bend out the chasssis. The covers slide better dissipating the force more or changing the absorbtion of the energy into a sliding motion. They also have rubber insterts underneath for direct force.
Now I'm looking at this from the point of view of mainly road use (mine is, afterall orientated more towards roadgoing journeys) where most spills likely to be encountered are going to be infrequent (hopefully), of the more dramatic variety or even of the silly kind like stopped as happened to me the other day. For all of those, as I say, I think the covers will serve me better. If I was going to use my bike for greenlaning, TET, RTW things where spills will be of various varieties, more frequent (hopefully not serious but offroading carries that risk) and on (generally) softer surfaces, then I would keep the bars, for sure. In fact, I'd probably have both, If I'm honest.
Personally I also think the bike looks better with covers than it does with the bars.
Incidentally colour is irrelevant, for a small price you can have them powder coated any coulour you like, including the same blue of the frame.