No keypad on public/industrial microwave ovens?

Factual Questions
1

I’ve noticed that microwave ovens that are being used in professional settings or are located in an environment (such as an office or university) where a lot of people might use them usually don’t have a full keypad. They either have a dial or have a series of pre-set time buttons.

Is this because:

  1. Keypad microwave ovens are more expensive?
  2. Keypad microwave ovens are less durable?
  3. Keypad microwave ovens are more easily mistakenly set for too-long times?
  4. Some other reason?
2

#3, mostly. Having a user interface that consists solely of butons labeled

Reheat beverage
Reheat plate
Popcorn
Stop

makes it impssible for some absent-minded (or malicious) person from tossing in a packet of popcorn and setting the timer for thirty minutes, thereby possibly causing a fire, and stinking up the place at the very least.

3

The ones that are set to types of food are owned by the vendor and meant for their product. I haven’t seen new dial ones for a long time. I have seen old ones. The mechanical timers were cheaper than digital ones and lasted a long time. This isn’t going to cover every situation you run into, but covers a number of them.

4

What vendor? What product?

When I say “public” microwave, I mean, for example:

  1. The microwave in the office pantry. There’s no vendor there. It’s for all employees to use to heat whatever food they bring in themselves.
  2. The microwave at the 7-11. You can use it to heat anything you buy there. It’s not tied to any specific product.
  3. The microwave in the student lounge. Again, there’s no vendor there. Well, there are vending machines nearby, but there’s no microwaveable food in them.

The ones in our office pantries are brand new dial models.

5

You haven’t been looking.

6

At my office the vendor of sandwiches provides a microwave that has labels for small sandwich large sandwich and the like. How am I to know you don’t have a vendor in your’s? The company supplied one is a digital you can enter what you want in.

For the two replies, what part of “This isn’t going to cover every situation you run into, but covers a number of them.” isn’t applicable?

7

The part where it’s unclear to what “this” refers.