Do you use your modeler as an interface?
Absolutely not. I have dedicated converters for monitoring, and other studio gear. Usually running a modeller as an interface is a nightmare by comparison, but works in a pinch.
Plug the analog outputs of your modeler into a separate interface?
I have all I/O from my axe fx normalled to a patchbay, so all the inputs and outputs run to the converter channels I want them too. If I want to send them somewhere else, I don’t have to reach behind the equipment. I also have reamp boxes and some pedals patched in to the modeller so everything is instantly accessible with minimal fuss (it’s all ready to go). Full flexibility with no downsides.
Skip the modeling hardware and just use plugins?
Despite everything above, mostly yes. I prefer the workflow. It’s easier, I can combine various plugins, change things and finesse. Easier to deal with saving settings and archiving sessions etc too. I don’t think it needs to be one or the other given the amount of cheap and free plugin options these days. Use both to your advantage.
I actually like committing to the sound early, but sometimes i’ll change a part or add something and it’s easier to just have a DI. I don’t have to recall different settings for different parts. Similarly, I might change key or tempo or a bass sound that means the guitar sound needs to adjust slightly now too. I can tweak amp settings or change IR’s without having to reamp a bunch of tracks one by one. It’s almost essentially to try to have something as close to the final sound as you can as it affects the performance and the sound of other things in your production. Make decisions and build on them - at some point you have choose and if you keep deferring them, you end up with an impossible mountain of decisions to make. The only way it works is to build those decisions on the back of previous ones - if nothing is set, then it’s impossible.
Do you record a DI for reamping?
Always, although I don’t have the mindset that I’m going to reamp. It just makes me switch a part of my brain off that makes me think I might have to retrack anyway. I like to record with the idea that the DI is going to cover all bases. Just handy to have too, you never know when you might need it later.