We do not have a guest room or any bedrooms with en-suite bathrooms. Unless you count the RV which does have a toilet and is often used by guests.
There is a sofa bed in dh's office and guests have the choice of sleeping there or in the RV.
Mostly guests are the kids friends coming for a sleep over. They choose the RV.
It is your house and you have the right to use it as your please. There are several here who have turned dining, living, master bed, rooms and more into sewing spaces. Some have converted garages (the car can live outside) or built dedicated rooms, buildings for sewing. Do what works best for your situation.