Most definitely not.
It is a different matter that all civil services are important. However, in terms of overall ambit, diversity and prospects, IAAS is far far ahead when compared to Indian Defence Accounts Service.
I will divide this answer into the following sections
Training: IAAS officer trainees are trained in Shimla at the National Academy of Audit and Accounts. Our training is primarily conducted in Shimla, with attachments with various institutes interspersed in between. In case of accounting services, of which IDAS is one, they are clubbed together for a major part and trained at National Institute of Financial Management, Faridabad. While this increases the size of the batch, it also imparts a college like atmosphere, which dilutes the seriousness and quality of the training programme.
Ambit: Defence Accounts Service is primarily concerned with maintaining the accounts of the Defence services. The scope of their work is pretty much confined to that. To work in other areas, an IDAS officer will have to go on central deputation. IAAS, even though has an “accounts” attached to its name, is primarily an auditing service. Audit is its primary function. This means that the service can work in any field to which the function of the government extends. You can work in areas ranging from Local body audit to Defence Audit. In fact, there is a Deputy CAG who is in charge of the Audit of Defence, Railways and Telecommunications. In short, an IAAS can work in areas where IDAS works, while it is not possible for an IDAS officer to do it the other way.
Facilities: Both IAAS and IDAS officers are provided accommodation which is pretty decent. IDAS score slightly better here as they are provided better accommodation and also can avail canteen facility. Official car is available in both services.
Diversity: Audit extends to all functions of the government. IDAS is pretty much confined to a single area.
Opportunities: IAAS officers have more opportunity to work both in India and in international organisations. IDAS can nowhere match IAAS in these aspects.
Exposure: CAG reports are nowadays so publicised and that gives much exposure to the IAAS. However, IDAS is pretty much completely away from the public eye.
Promotion: An IAAS officer will reach Higher Administrative Grade in 25 years. An IDAS officer will take 28 years for the same.
IDAS is a very old service which serves a very important role. But if you are a UPSC aspirant who is looking to fill your DAF, putting IDAS above IAAS without a very strong reason would be an incredibly foolish decision that you will regret later.