Absolutely book this airbnb. In addition to being located well (no more than 20 mins walking to any of the sites we visited) it's right near the palace of dueñas, which has lovely gardens you can walk around in before/after checkout if you have time between your next appointment. The host provided us with a full list of her favorite restaurants and museums as well as details about what districts were where (e.g. old Jewish quarter) which was amazing.
As for the unit itself It has a small courtyard patio with 2 chairs that you can relax in at night - it stays warm in Seville (it's also perfect for drying clothes). The bedroom has a sliding door; I thought the shower was more spacious than other airbnb's I've stayed at in Spain. There's also a small balcony on the front. Wifi worked fine, it was quiet at night, and the curtains did a good job blocking light so we got to sleep in.