The Dark Lord did think them loyal enough to be worthy of honor.
When the Dark Lord returns to his full strength after the restoration ritual, he says that the Lestranges are in Azkaban and will all be honored when they are freed.
“The Lestranges should stand here,’ said Voldemort quietly. ‘But they are entombed in Azkaban. They were faithful. They went to Azkaban rather than renounce me … when Azkaban is broken open, the Lestranges will be honoured beyond their dreams.”
- Harry Potter and the Goblet of Fire, Chapter 33 (The Death Eaters)
Since he says “the Lestranges” in the plural form, that means that the Dark Lord did consider Rodolphus and Rabastan as being worthy of being honored as well.
Bellatrix also thought everyone who tried to find the Dark Lord would be rewarded.
“The boy’s three companions rose quietly from their seats; the woman with the heavy-lidded eyes looked up at Crouch and called, ‘The Dark Lord will rise again, Crouch! Throw us into Azkaban, we will wait! He will rise again and will come for us, he will reward us beyond any of his other supporters! We alone were faithful! We alone tried to find him!”
- Harry Potter and the Goblet of Fire, Chapter 30 (The Trial)
From what the Dark Lord himself said, he considered Rodolphus and Rabastan worthy of some honor. As for why the two of them weren’t given bigger roles in the war, there are two plausible options. The first is that they might not have been suited or capable for a larger role. For example, doing what Crouch Jr. did took a specific type of talent at acting, not just loyalty to the Dark Lord. The second is that they might not have been quite as loyal as Bellatrix and Barty Crouch Jr. and so they were favored, but to a somewhat lesser extent than Bellatrix and Crouch Jr. were. This seems to be likely - both Bellatrix and Crouch Jr. clearly showed a very high level of loyalty to the Dark Lord. Even though Rodolphus and Rabastan seemed fairly loyal from what we know of them, they may not have reached quite the same level, and therefore weren’t honored quite as much.