I'm in the UK, I've been in four times now.
firstly they have no beds so they will most likely try the CRISIS or CATT team first who provide intense support in your own home, if they can't manage you or you want an admission and they agree it might be helpful you can ask for one and they'll start looking for a bed. It could be anywhere in the country so just bear that in mind.
I was voluntary twice and sectioned twice. I would always always recommend voluntary admission and avoid a section like the plague. You have more control as a voluntary patient, you get leave quicker- get off the ward- al NHS sites are smoke free now but some are stricter than others. Fortunately I've only been to my local ones but they don't vapes or smoking but as soon as you get grounds leave you can do that.
In terms of if it helps, for me, no, but it might for you. I don't see what the CATT team can't do that admission can do whilst you keep your own comforts. They have their own consultant to change meds, can see you everyday etc. but if you feel you can't keep yourself safe aside from their visits and you want to try and get better then hospital might be the answer to try.
First, I'd ask for a referral to the crisis team they are the gatekeepers in my area for hospital beds so you would have to be seen by them anyway before being in hospital.
Feel free to message me if I can help answer any other questions or support you x