Kenny, my reaction was the same as Oscar's. I immediately though of using in my bench accessory slot, rather than in place of flat barbell bench. I'm currently doing flat bench DB presses as my accessory. Would it be better to keep that as accessory and switch in floor press in place of BB bench? And do you usually do BB floor press or DB?
To be honest, I think both would work. What's best just "depends". If you're already doing DB bench as an accessory, then it would be really convenient to just switch that for DB floor press and have minimal impact on the set up of your current training program. I would suggest this as a first port of call, actually, to avoid that urge we lifters get when we read or hear about something that sounds good on paper and want to build our whole program around the new information.
By using DB's, all you really lose is specificity if the goal is to help increase your bench (you know, for the life of me, I always have trouble pronouncing "specificity"). However there is a trade off. If you have the notion to do this based on the shoulder-blade-feedback Ken mentioned, then DB's will be fine and I would still think you would see some carryover to BB bench if it allows you to dial in on this more. If anything, you feel what's going on with your scap a little more with DB's so it may even be a better place to start.
I usually do BB floor press, as opposed to DB's. I do use DB floor press though. I've used it on and off in my own training and also with clients. Being honest i've mostly used it with clients who have shoulder issues, we just go to floor variations to limit shoulder rotation whilst we correct the issues they have. I have intended on giving the DB variation a little more love in my training for months now but, just not had a chance to fit it in yet (my accessory choices are limited due to time constraints, so I only add things that I know I can do consistently).
In terms of the "variation without change"/switching out the main lift, sometimes I think half the benefit lies in stopping the original variation, in this case Bench Press. For example, when was the last time you went more than 1-2 weeks without BB bench pressing? Most people rarely go 1 week without BB bench pressing. I think it was Pavel, but not certain, that said (paraphrasing again), "to adapt to training is to never adapt to training". Ideally you want to be adapt-ING, but you never want to have "adapt-ED". This doesn't mean you need to change your lifts, though. Most will do this by fluctuating load, intensity, reps, rest, etc. However, we adapt to exercises, too, not just rep ranges. So changing variation is another road to go down in this respect. Sometimes i'm not sure if it's the variation that makes us stronger or the lack of training the original lift that helps, but it's probably both.
So, um, in short, I would try going down the assistance route first. Remember all you really need is to see improvement in it then see what that improvement has lead to, if anything. For example if you start off with 20KG DB's, and 8 weeks later you're doing it with 30KG DB's, what has happened, if anything, elsewhere? It can get complicated attributing improvement on one thing to just one other small part of your training but, if you add something in and something else jumps up more than usual or improvement takes place where you were otherwise relatively stagnant, then you can be sure it had "something" to do with it and gives you more reason to do more of the same.