how do most providers really feel about a finger or two in the vagina?  I usually have a professional manicure before any session.

I am very susceptible to bacterial infections. One guy poked me so hard that I started bleeding (not cool).

.schtankbox is beyond me

Some like it, some don't. Ask the one you are with at the time!

What is it that hobbyists who finger-bang find so appealing about putting your fingers in a woman's vagina?  Do you orgasm from it? Does it bring any sort of sensory stimulation at all?  Is it a simple reliving of teenage memories?  Is it "for her pleasure"?  Just something to ponder...

.............some gals will actually beg you to put your fingers in there. Short, clean finger nails are a must.

Depending who is doing the finger-banging, and how this finger banging is executed I can, personally, attest that a 'finger-bang' can be very, very good.  

She says that it doesn't begin to compare with my dick, so get to it.

I routinely get manicures and have had providers comment on how nice my fingers look.

She's VERY particular and VERY precise about what she likes regarding manual stimulation. She's 100% GFE, but in this activity, it's total Tantra. Amazing!

If you plan to do this, please use the sink and wash your hands when you arrive.
Please do that anyway.. It takes less than a minute...

to arrival.  WHEN I arrive I take care to thoroughly wash including my hands.  It makes sense to me...  I will likely have used a bathroom, touched elevator buttons & door knobs...   I have soft soap in my go bag!  
I like to offer DATY...  gently & let her guide me.  I might cup her bottom as she moves against me but I am just the engine & she is always the driver.  She can feel my tongue & lips...  and fingers...   I pay attention to her responses & desires...   I can not "make" her cum.  If she chooses that choice I am happy to do my part.  I typically end up with a pretty wet face...  sometimes requiring a towel...  

During DATY it's really nice.

Yeah, yeah. I know. You all saw that one coming a mile away. Lol.

so I love to chance to gently explore and pleasure a lady and to feel the warmth and softness of her inside.
Is quite a turn-on to me.
I've had several ladies take my hand directing me to do this too.

FIV not so much but I do like a finger on my clit clean fingers of course that goes without saying.

It's also not so simple as just stuffing a couple of fingers inside her and "banging."  It's usually very easy to find her G Spot and massage it with a "come hither" stroke.  Combine that with rapid and delicate flicks of your tongue on her clit and magic happens.

I would tend to agree.  On the occasion when a finger or two was welcome it has always combined with oral stimulation.  In any event, guys just need to use their heads (the big one) a bit more.  If it's not already wet down there shoving fingers in is usually not the way I would start things off...