Do I need the Google Voice app?

No you don't need the Google Voice app for that. Nowadays about the only thing you need the Voice App is to allow Google Voice to serve as you voicemail instead of your carrier.

 

You can use the GV app for voicemail/SMS/MMS or you can use Hangouts. HO's can be used for your real number and for GV, everything all in one spot, it's convenient. You can use your regular messaging app and the GV app separately if you want.

I use both apps for a few reasons; HO's takes forever for a voicemail to arrive, I can't just delete the VM from an SMS thread (OK, you can but it's a pita) and HO's sometimes is way slow in general or fails to send/receive texts. So I use Chomp and the GV app. BUT, I am on Verizon so the GV app doesn't really handle MMS well at all, pics go to my email, another pita. My GV is used for everyone besides family so I don't run into that often. I think some carriers handle that better than others so it may not be an issue for you.

I'm still waiting for the perfect solution, I think I'll be waiting for a long while though.

 

Calls, yes because they are forwarded.
Voicemail, yes because the calls are forwarded.
Texts, maybe. That's sort of the gray area. You'll have to play with settings in GV and your phone to see if you can get them to forward to your messaging app. You may have to use either HO's or the GV app for that, although my sister uses the Verizon Message+ app (or whatever it's called) and that does handle GV so...

Google Voice is a great thing but in some ways is still stuck in the early 2000's. It hasn't been updated in forever. The GV app itself is sooooo basic. It's Google's red-headed stepchild. lol

edit: You can forward your GV texts to your messaging app, they just show up with random unknown numbers, not necessarily the number it's being sent from. MMS/pics probably will still be messed up too, at least mine are.

 

I don't use Google voice. For voicemail, I use Instavoice.

 

Yes, you'd get everything in HO's. Text, MMS, voicemail (if you use GV for that) for both your GV and regular number. One stop shopping

 

Guess I'm too much of an ole fogey, I just can't see a need for Google Voice or their telephone numbers.

I use Google Voice Search, but that is all.

I stay strictly on Verizon's services for everything else, MMS works just fine for me including pictures.

 

Disabled. Had a GV number, never used it and gave it back.
If you pester as a spammer, I have a very good call blacklist app. If I've done business with you, you have my email. Use that.

 

It's convenient. Got it in my Lg. I do not like such apps but Google is an exception.