I have been down this road and I wouldn't do it again.
At the time it was post-Bacon report 1 and mortgage interest relief was not available on investment properties generally. I bought one which came under the seaside resort scheme (sort of a special case of Section 23) on which interest relief was still available.
Income from holiday lets was sporadic, and subject to lots of extra costs like cleaning between lets, management fees and commissions, registration with Bord Fáilte, etc.
It would have been a lot less trouble and certainly higher income to do normal long term lets, but it was a condition of the tax relief that the property had to be available for holiday lets. In the absence of that sort of tax relief, it would definitely not have been worth the hassle.
The one other reason one might consider this is to have the property available for one's own use from time to time. I still think you'd be better off separating the issues of investment and holiday use. Get a property for long term let and use the rental income to rent a holiday home from someone else!