Glass Carboy for primary?

My Friend has suggested that since I'm buying more decently expensive stuff to start out that I may as well purchase a 6 gallon glass carboy to use for my primary (5 gallons for secondary). This is so I can put a thermometer inside the carboy itself while it is fermenting in a chest cooler to get the actual fermentation temperatures, and because glass is just better anyways?

Just thought I would get some other opinions to validate my purchase

You can. But no need to. 6.5 gallon Buckets are cheaper, and they don't explode and send brewers to the ER when bumped wrong.

I try to only use glass when aging.

Nothing saying you can't, but you can use that money saved on other items. Also, sometimes 6 gallons isn't enough head space for a brew.

Carboys are all I use(except for must buckets).
I find them easier to clean and I don't have to mess with lids.

eventually you collect multiples of the whole set. 3, 5, 6, 6.5, 8.9(DJ), 15(DJ)
6 gallon works great for a 5gallon batch primary.