I think hospitalisations can be beneficial sometimes...
I have heard that they can be used at strategic times such as when abuse memories are just beginning to resurface.
Or if someone is in danger of hurting themselves / someone else.
Would you be able to continue working with your current t if you go in?
Continuity of care can be important.

You do have to be a bit careful about whether there is anyone there who specialises in DID or has experience with treating it. Same with regards to the nurses etc. Also about their policy on treating it.

Therapists / hospitals that are more sympathetic to the post-traumatic model would provide a very different sort of treatment from ones working more with the socio-cognitive model (which seems to endorse 'punishing' alters by making use of seclusion) for instance.

I'd say you would want to find out more about it before making a decision.

Do they have an inpatient treatment program or will you be fairly much left to your own devices?
Art therapy?
Sports?
Therapy?
Etc etc.