Technical support is assistance and problem solving given by technical personel, either internal of a team or outsourced.

Internal technical support should be explained first.
Internal technical support has technical personnel as part of the same team or organisation. Organisations that do not have the volume of work to maintain full time or part time staffing, can instead use contracted technical support on an on-demand basis (i.e only when needed), and this is refered to as outsourced technical support.

There is not a yes or no answer for this. The expense is the purpose or project that the technical support serves to buttress and not the technical support itself, even though you can get varying costs for the same support from different service providers.
In every case, once there is competetent management by the organisations choosing and implementing the technical support, there should be increased results via upskilling or income, increased protection from equipment loss or damage, and in the least pay for itself.
The subscription method developed by Pro Spirit removes the up front cost and spreads it across a 3 - 12 month period whilst having the intrinsic feature of ongoing support.

Any one of the following. Organisations that are understaffed, have mostly unskilled workers or volunteers, operate on a low budget, occasionally conduct projects or events that are bordering or outside the scope of their skillset.

Advantages
Access to knowledge, expertise, technology at scale, with savings, whilst still focusiing on the core responsibilities of the organisation.
Disadvantages
The disadvatages are little to none once you keep your internal technical support staff informed prior to outsourcing and every step of the way to avoid low staff morale. Also keep in mind that you have low managerial control over outsourced technical support as it operates on contract stipulations and not your organisation employee, volunteer or member rules. In which case outsourced technical support will operate under more stringent self imposed guidelines. This operational difference will usually cause friction between internal and outsourced technical support and should be dealt with as a normal and integral part of operation / integration.