Is the LG 32BR50C-B good for gaming?

It handles casual and console-style gaming well thanks to 100 Hz and FreeSync. Competitive players will notice the 5 ms response time and some motion blur on fast scenes.

Is a 1500R curve too aggressive for office work?

At 32 inches the 1500R curve is noticeable but comfortable for a single user sitting centered. Spreadsheets and documents look fine; the curve mainly helps immersion in video and games.

Does it have built-in speakers or a headphone jack?

No. There is no 3.5 mm audio output and no built-in speakers, so plan on external speakers or headphones connected to your PC.

Can I mount it on an arm or wall bracket?

Yes, it has a VESA mount. That is worth using because the stand only tilts and does not adjust height, swivel or pivot.

Is it good for photo or video editing?

Not ideal. The VA panel has strong contrast but shifts colors when viewed off-center and offers only 8-bit color with no HDR, so color-critical work is better served by an IPS display.