I've used it with the $50 roam plan as well during the Helene aftermath here in SC. During off peak hours the speeds are really good, but during the "peak" time from about 8-10pm at night I found the speeds were slower due to more people using it during those hours for streaming, etc. My understanding is Roam customers are at the end of the totem pole as far as prioritization, etc. but the speeds were still fine in my case.
We ran our entire home network- TVs, PCs, mobile devices, etc. off it for 2+ weeks until Spectrum repaired their lines. I still use it when traveling, pausing it as needed.