Learn Hardcore Russian: Почему бы не заказать столик заранее, чтобы не стоять в очереди у входа? - Why not book a table in advance so we don’t stand in line at the entrance?

Почему бы не заказать…? is a very common way to make a friendly suggestion: Why not…? / How about…?
It’s not a real request for a reason (почему), but a polite prompt to consider an action.

Structure: Почему бы не + infinitive
Examples:

Почему бы не пойти пешком? = Why not walk?
Почему бы не попробовать? = Why not try?

It often feels slightly softer/more conversational than a direct imperative.

What is the role of бы here? Is it the same as in the conditional?

бы is a particle that often adds a hypothetical/softening nuance. In Почему бы не…, it makes the suggestion sound less direct—more like it would be a good idea to….
Yes, it’s the same particle you see in conditional-style phrases, but in this fixed suggestion pattern it’s not building a full conditional sentence; it’s mainly giving a mild, “would/could” flavor.

Why is it заказать (perfective) and not заказывать (imperfective)?