Sure, it's fine to use whatever voicing you can make work. 

But it's always a good idea to keep working on other voicings especially for more musical options.  

Depending on the context of the music or song you are playing these options might also work.

Open B7 chord:

|--2-------------|
|--0-------------|
|--2-------------|
|--1-------------|
|--2-------------|
|----------------|

I know you mentioned holding down the B on the 2nd fret A string, but have you tried the B5 power chord (with 2 or 3 notes):

|----------------|
|----------------|
|-------4--------|
|--4----4--------|
|--2----2--------|
|----------------|

This is often a good step toward the A-shaped barre chord, and you don't even need the high E string.  Fret the B with your index & use your ring or pinky to barre across the D, G & B strings.

|--------------|
|--4-----------|
|--4-----------|
|--4-----------|
|--2-----------|
|--------------|

So for now keep using that E-shaped B barre chord rooted at the 8th fret.  And keep working on other voicings!  Hope that helps!