Linear models, so not even deep learning models?
Sure, you've got the quintessential marketing induced ML overlay that many firms do, but in all cases I've seen so far it's completely defanged and really there only so that it can serve as a marketing move.
At lower frequencies when the data gets thin and noise/overfitting is a major problem, yeah it makes sense to use simpler models. Bias/variance tradeoff in action.
On niche markets with low liquidity, one doesn't have such tight latency envelopes but those markets also offer more opportunities in general so again there's no real justification to use fancy ML models or GPUs in general.