The imagery of the 'coffee battery' is at the least quite evocative. The proto-machineguns might be too immature a technology to carry the day for now, but one might imagine that this company could be assigned a mixture of artillery and machineguns in future wars based on this precedent.
While proto-machine guns are certainly scary weapons, their battlefield effectiveness was always questionable at best. Prone to jamming, overheating, and a myriad of technical problems, these weren't war changing weapons. Despite many
many writers wondering what might have happened were guns like this employed
en masse, the sad truth is they probably would have been cumbersome burdens on the armies they were employed with. Just keeping them supplied with ammunition alone would have been a logistical headache that I don't imagine any officer would have been thrilled to tackle.
The quintessential example really is the French mitrailleuse from the Franco-Prussian War, where a combination of flawed tactical inception and staggering Prussian artillery superiority meant that even when the guns were used effectively, they were never tide of battle turning weapons. The example here would be where even if a Union battery got a Gatling gun or the like into battle properly, on the field an Armstrong gun (or even a Union Napoleon) is going to rather effectively turn the tide due to range superiority.
Despite some thinking that General Ripley and the Ordinance Department were too conservative in their thinking, I do think he was right in deciding that repeating weapons were
not the right weapons to arm the US in the Civil War. Just expanding the 16,000 man peacetime army to a paper strength of 500,000 men come the start of 1862 was a daunting enough task that the thought of trying to arm them all with weapons that were still in their teething stages is something I think any soldier worth their salt would have nightmares about! The
future of warfare though, is probably going to be seen effectively in some cases.
While the campaigns haven't reached the Overland level of trench and re-trench warfare we saw OTL, now that the armies are moving, you can be sure that the pounding around Washington and the vicious fighting at Savage Factory and the Patuxent means that no one really wants to be dodging bullets out in the open anymore.