Learn Turkish: Otel olsun, çadır olsun, tatilde konfor benim için çok önemli. - Whether it's a hotel or a tent, comfort on vacation is very important to me.

The olsun ... olsun structure translates to 'whether it be... or...'. It emphasizes that no matter which of the options is chosen, the outcome remains the same. If you just used veya (or), you would lose the 'whether it is' framing and would need to restructure the rest of the sentence to make grammatical sense.

Is olsun here the same word as the imperative form of olmak?

Yes, exactly. It is literally the third-person imperative meaning 'let it be'. By repeating it after different nouns, it creates a fixed phrase that essentially means 'let it be a hotel, let it be a tent' which we naturally translate as 'whether it is a hotel or a tent'.

Why do we use the locative tatilde here instead of a time-based word like tatildeyken (while on vacation)?

Both are grammatically correct! Tatilde simply means 'on vacation'. Using tatildeyken (while being on vacation) is also perfectly natural, but tatilde is more concise and very common for expressing states like this.

Why doesn't the sentence end with a 'to be' suffix like önemlidir?