Smoking pen???? SOS

I’m fairly new to the whole wax pen or vape pen (idek exactly what they are lol) trend. I’ve only ever smoked flower since high school and I tried my friend’s smoke pen a few times and really enjoyed it for how convenient is it to just carry around. I was looking to buy once but realize there are different types??? Or are they all the same size? For instance: the pictures below...

The top one simply says wax pen and the bottom is for cbd oil... only??? I’m confused on which to buy... SOS haha

Edit: I’m looking to buy one for its conveniency. Not bc it’s trendy... it’s much easier to carry around a pen then actual flower and equipment to smoke it lol.

Anyways thanks for advice